GM 12-Bolt rear diff UPGRADE: Positraction and gear swap | Hagerty DIY

let's start it that way hi this is David with Haggerty in our DIY series today we're with our 1969 Camaro you might have just seen the video of the redline rebuilt for the engine and the motor is making a lot of power it's feeling good but if you notice that the end of that video which is a link right here then the link is over here then you'll see at the end that this has a one wheel peel which is all fine and dandy but we want to make it a little more exciting to drive in purposeful so doing that we are today we're going to take and we're gonna change out the carrier this is an open differential and we're gonna put a positraction carrier in and then while we're there we're gonna change this anemic 308 gear to a 342 now what that's going to do for us is that's going to give us a little more grunt coming off as acceleration is concerned and then we're gonna sacrifice a little bit of a highway cruising but really we're only gonna lose about 300 rpm so instead of cruising at say 2500 at 65 miles an hour will be about 2800 at 65 and that's not really enough to get too concerned about yes big blocks don't like the high Rev rpm for a long time but we went through and we balanced that motor and it should run nice and smooth at the higher speeds and not have any issue whatsoever so with that where I'm at right now is I've already pulled the wheels off now let's be honest if this is a job that is not that difficult I thought of five I would put it at a three maybe a four there are a couple things that are very specific to do in this and that but it's nothing that's insurmountable however if you're struggling pulling the wheels off that's fine and dandy this project might not be for you but if you got it that far you're gonna be golden alright so I need to pull the drums out of the way so I can get to the axle ends because there our C clips in here that hold the axles into the carrier and then there's also this cross shaft so pull get the drums out of the way and then the axis will be able to slide out once the cross shaft is out C clips come off and and then you put axles completely out of the way that way this carrier will come out otherwise the axles are holding it our tools that we're gonna use today are fairly simple and straightforward basically need some way to remove the wheels in this case I'm using the impact you could you obviously use a hand wrench now you also have you know just a simple ratchet and some general hand tool wrench wise you will need a dial indicator that the reason for the dial indicator is so you can set the lash which we will get to and then you need some way to put the bearings on to the pinion or in the carrier we're gonna actually use a 50 dollar oven we picked up over at a local box store and that should get us plenty warm expand the bearings and they'll slip right onto the onto the pinion okay I have my brake drums off and obviously I have the drive shaft out because the pinion is going to come out I have to take the yoke this way pinion comes this way and I have removed the rear cover now real simple recovers held on by 12 bolts in this case it is up here it is full of fluid pull out all the bolts but what you want to do is as you remove the bolts have a drain pan right away just tip this out a little bit let it drain get all the gear lube out and you have access to the gears that way okay now like I said in order to get the axles out I need to remove these seat clips that are in here now in order to move the seat clips I have to get the cross pin out because you actually push the axles in a little bit and that allows the C clips to drop out there's a cross bolt here it's and this particular one's a half inch need some way to hold it from rotating in order to get that out and it's not a ton because it's fairly small now with the pin now you reach up here and you can push down the cross shaft cross chef pulls all the way out so the cross chef has this hole that that's where the this pin went in to hold that into the carrier so the function of this cross pin is it holds the spider gears in top and bottom and then also maintains the axles from coming in too far and the c-clip dropping out all right so the axles in c-clip drops out and that's what that's what's retaining that axle and I come from this side like pull that up same thing for the other side now you certainly you may need a magnet to grab a hold of this as well now something I like to do just because is so the spider gears don't fall out I put the pin back in I don't hold everything together when I pull it out we're not gonna reuse the carrier obviously but it makes it a little more easier to handle here to pull the carrier it's just these four bolts that hold the saddles in here yeah like a main cap on an engine let's hold those in there that's where the bearings are at now there's also shims between the housing and the and the carrier and that sets that preload and backlash relative to the gear and the bearings so to do that just uh just the ratchet these are torqued in and about I think it's 65 foot-pounds so it's not too bad to break them loose obviously they're gonna need a torque wrench to put him back together correctly if I'm reusing this carrier one of the things I want to make sure I do is keep the shims right to left as they come out and then also be bearing races because I want to mate the bearing races back up with the the bearing that it was already functioning with just eliminates a potential problem with mismatched call it mismatched parts where they're broke in and wore in together all right so here's our bearing cap off in if you look at it's pretty similar to what an engine has certainly not as large but that's that and this right here is our race and then you can see one very large shim here and there's probably a smaller a large shim and a smaller shim over on this side and you do want to keep your bearing caps relative to the side it came off of so this was here like so not a bad idea to mark them as well and I will just keep them organized on my table further I'm being now to pull to carry out the rest of the way again I mentioned it has preload on it from side to side so it's going to take a little bit of prying to get it to come out of there and try to keep your hard to keep your shims together and it's just as a point of reference as you as you go now in theory you got plenty of room and your mufflers not in the way but we got just enough space so this is how its assembled you have your your bearing that's pushed on to your carrier you have the outer race that just slides up into the main housing and then this is the right side shim and obviously your left side chimp again and we'll go through this as we go set the back the other piece GM has multiple ones of these size wise and they're always real you know the big thickness take up all the gap and we go over to the table you see that we have a bunch of smaller ones and thick ones because we're gonna adjust this we have a little finer adjustment that way and we will need it because we're now have a multitude of thick ones on our shelves I highly recommend that when you buy your bearings you actually buy it in kit form so when you get your bearings you will get all new shims both for the carrier and for the opinion and then you get all your bearings and races and the opinion seal you also get a gear marking compound and then new bolts relative to the ring gear and a nut retainer and the crush leave which will we can go through that on the table as well how about all laid out but definitely by the installation kit if this is your first one you might not need the installation kit the second time because you typically have more shims than what you need but on the first first go-around buy the kit so here's our empty case we still have the pinion in I needed to take my impact and pull the yoke off the front side and then that pinion will push out this way okay there's a nut and a washer the nut we will not reuse but the washer we will and that'll come out here whenever it'll come out right with the yoke air so a couple taps here so here's our washer now when I was hitting on this I made sure I didn't hit on the ears I hit on the beefiest section which is right back here and rotated to wick to work it off now this is a slip fit onto your spline of the pinion but it does have a tendency to kind of hang on to it after it's installed with such force and lots of times you also put a little sealer on here so gear lube doesn't seep up the splines alright the pinion is in and it has two bearings on it one that's pressed on to the bottom of it by the gear but then the other ones up higher on the head here in basically there is a little bit of a it is tight take a little bit of effort to get the pinion to come out to know what to hit out of the hammer and not is uh I'll say by experience of oh shoot I shouldn't hit that with a hammer so note that I did not use a standard ball-peen hammer I use it what's considered a dead blow hammer so this has lead shot inside of it it gives it a little bit of beef and it will not Mar up the threads now if I didn't have not did not have a dead blow hammer now let me get this pinion you know if I didn't have a dead blow hammer there's absolutely nothing wrong with taking this nut and threading it on and basically sacrificing the the nut now you want to you could bring it down enough to where it was call it flush with the face of the yoke but or the face of the pinion and then of course you know hit out here there nothing wrong with that at all you could also use a wooden block as well yep basically you want to even though I'm not going to use this gear again at least for this car you never know what scenario you might have and if you're using let's say you are pulling it and you're you're actually just changing bearings because these bearings will go bad on occasion and you were gonna reuse the gear then you certainly don't want to kill the threads out here this nut is a lock nut so it does bite on there that's why you don't reuse the nuts in but you want to save the thread a block of wood a dead blow hammer even a brass hammer or at least a piece of brass in between the hammer and the and the and the thread would also save that alright now we have our carrier in our opinion out of the way I need to knock this pinion seal out and then the two bearing races [Music] so even though these bearings aren't all that old and the seal wasn't old I got brand new seal and all the bearings in the kit in the installation kit so that's why I'm gonna replace these and of course it's not a bad idea to do it anyway because just like Murphy's Law it might not be leaking now but I will but soon as I don't replace it there's a little flat spot in here to reach in on both sides you could use a puller butt off in this case a chisel but a long punch works just as good and you want to work your way around it because as it comes out it's gonna wanna talk sideways [Music] and you want to take your time again just walk it out nice and slow so you don't Maura the bore so this is the area in the housing that's been cut away in the casting so you can get a punch in to take these bearings take the races out let's go over the table well show you show you what we got going on over here for the assembly and so here are our brand new ring and pinion these are a match set from the factory what they do is they take and they run these in which if you want to think about it is they're mating them together so they're spinning these and setting them up now if you can see real lightly I can kind of see where that rare wear pattern is at it's right about here it's hard to tell with the black on it but you with a light right you can just see it what we're trying to do is set it up into the housing recreating that exam exact we're not to do that they've provided us the numbers on the back side it says looks like 2-inch 871 so that is the depth of the pinion so when you measure to the centerline of the bearing caps to the face of this that's gonna be 2 inch 871 so it'll sit in the gear like that and you're gonna measure here to here Bob viously in the housing and I'll show you that for this we have also we have this brand new posi track carrier that has bearings up on it already the side bearings will go through putting the pinion bearing on using the same method the with that comes new races and this is all the stuff that's in the installation kit so you have the new races relative to the bearings we have the new front bearing and then we have a new back bearing which X is this one now this is gold because I actually heat it up in the oven already just to understand my expansion so these bearings are pressed onto this shaft now you can press them on or you can heat them and the bearing will expand such that it'll just drop over the top of it and you can do this fairly cheaply we went over to box store and picked up a I think we spent $60 on a toast and we'll show you how that will work to do this now during the set up like I said we need to we need to take and set this pinion depth and to do so we have to have different size shims that will be placed underneath between the pinion and the bearing now this is a brand new bearing on the on the tail or a headstock side of it I'm using the exact same Timken part number bearing this is a sacrificial one I took a grinder and opened up this ID so it slipped fits on to here bearing tolerance is relative to the stack up here are so tight that we don't have to use the exact same bearing to get our installation done this will mitigate us pressing this on and pressing it back off to change this shim as we as we need so that's why that's done that way I'm going to do the same thing with the bearing we just pulled out this is the the old bearing in there I'll show you how taking just grind this out until it slips fit onto here same idea is I can put this on it meant it it makes the the assembly mock up procedure a lot smoother will also need the opinion or I'm sorry the yoke the yoke pushes on here and we'll just get it nice snug fit so the theory is is the race that's in the housing will be nice and tight here so it's in position in the housing and then I can measure this back and forth and I need to be right around 2 I think the spec on it showed plus or minus 2000 so I got to be fairly fairly accurate with that let's get this open back up this is the new one we want the old one so let's open up this old one real quick the idea is a nice little sanding roll I'm gonna take a look just hold it my hand is fine it will not get that hot to wear you can't hold it if it does grab a glove [Music] so press fit on a bearing to a shaft is typically around mm if you go too big it's not a big deal in this all we're doing is making a setup piece so the idea is it's gonna slip on nice and come back off purely for setup you would not want this in your final installation all right so now we have everything we need to get our pinion set up next we need to go put these fresh races into the housing the area it goes into it needs to go in square and flush to the stop so you certainly want to clean everything out make sure there's nothing in there that's fell down casting whatever it might be that looks pretty good of course my parts nice and cleaned set it up in here these first couple of hits are gonna be a little awkward because it's kind of fine gonna find itself but it sounded like she hit home now I know it bottomed out because you can hear the pitch change so it was a dull thud until it bottomed doubt the race bottoming out to the housing you can hear that pitch change it's plain as day I usually hit it one more time to make sure I wasn't hearing things and of course visually inspect it and I'll check it from the other side as well all right now the other side winner winner chicken dinner now if you had a question of whether you were not a hundred percent to the to the stop you certainly could go in with a a small punch and hit right on the edge of this but it better be really careful because it's real easy for that punch to skip off that short lip and then hit your bearing surface and you could also look for well can also well look from the other side and you can see that ledge and make sure it's up against it nice and tight like I said now we're gonna take and we're gonna set this pinion depth so again from the center of the axle to the face of the pinion is our depth this mesh this from the factory is 2.8 7-1 inches so let's from the from the centerline to the face now first thing they'll tell you in every direction kit I've ever looked at is a question of well what gym should I put where should I start well guess what first thing I want you to do is I say well I'll use what was in it so there this one you could take that all apart and figure out what shim is in there and that'll get you awful close that's their quote unquote starting point I'm gonna do it a little different quite frankly I went through my shim kit and I find I have more 30,000 shim than I do anything else so that's where I'm gonna start now in theory I can just hold this if if I have hit somebody else I can just hold this right here hold tension on it but what I'll do is actually assemble it using the yoke so the washer up there and I've cut down the nut to take away most of the retention feature so it'll just turn a spin on I still have a little bit left though so I'll have to overcome that take up the slack in the bearings with a nut right there it's just snug that's all I'm looking for so the dimension I need is the face of this pinion to this surface which is where the main caps go on which is in the centre of the bearing carrier now I need to measure down like this of course I'm going across that an angle so I need to project this surface over the top of here and so I can measure my distance correctly now there are tools available that you can purchase they are they range from $100 I've seen them up this far as $400 granted the 4 or $500 ones are a little more Universal they're gonna have a bunch of mock bearings to go in here and a bunch of other stuff and fit multiple axles and then there's also the style that just kind of bolt on here and then come across then use a dial indicator they tend to be okay and but what I've always found is that a simple piece of steel and in this case I'm actually going to use this surface but a simple piece of steel bolted up that is flat and is solid this is a 3/8 chunk of steel okay and I'm going to tighten this down so it's not wobbling around now you're gonna say all right well how do I get the measurement you said you have to measure from the bear cap to the pinion that's 100% correct but you can do a little math and if you measure so now I'm going to measure the pinion relative to this surface down to the pinion face but what I'm going to do then is subtract the distance from here to there and on a pair of calipers you have the function to zero so you can put this in any position hit your zero button and then anything after that will automatically do your math for you now the only problem with that with this using as a depth gauge you have a very small surface area to locate off of so it's critical that you feel the flatness and I tend to measure it multiple times and get a repeatable number one 85-86 so yeah so I'm gonna take in zero this at 186 now I can come into this hole do the exact same thing down to the pinion and I got 2.88 call it for I think my number was 71 so I need to add about 12,000 shim underneath that bearing to bring the pinion face this way 185 86 so yeah so I'm gonna take in zero this at 186 now I can come into this hole do the exact same thing down to the pinion and I got 2.88 call it four I think my number was 71 so I need to add about 12,000 shim underneath that bearing to bring the pinion face this way but I'm gonna recheck it a couple more times so I'm gonna add twelve thousand two that hopefully my kit has all those it should I need a total of that's basically 30 29 so I need somewhere around 40 basically call 41 if I get to 44 all right so I need 41 42 somewhere in that range this is 21,000 I'll let's stack these puppies together I get 42 thigh perfect let's try that we have a two point eight seven zero we need two eight seven one spec says within two thousands so that's money right there so now we know we are we have our opinion shim we know what it is now we're gonna take over to our back over to our table we need to get the new bearing put on there with the shim in the way and then it's ready to be installed into the housing for good alright now we have our pinion bearing set we know what shim we need but note that I have other bearings on here right and I have a mess of shims before you take this off do yourself a favor get the other shims out of the way so you do not mix them up and secondly you'll notice that I've also marked my bearings with the marker so I knew which ones were the used bearings or the ones with the open hole not that you wouldn't realize it when you go to press them on but now it's also a good time to get these out of the way so you do not mix them up with the brand-new stuff so here's our two brand-new bearings the one that needs to get has to get pressed on is the but larger one for that I'm going to put it over here in our fancy a little toaster oven that we got you can see it's brand-new sparkling we've yet to have any pizza in it which we will take and put this all the way up for ha 450 and I'm gonna do broil even though it has a turbo function which seems to be really cool get about yeah I'm gonna give it 20 minutes I'd be more than more than plenty of time so we'll let that heat up it's going to get nice and hot I'm as soon as that goes off I'll grab it with some gloves bring it over here and it'll slide right on down the home now before I do that I do want to remember to put a little bit grease right here on this area because it will help that bearing to slide mainly because steel against steel tends to drag a little bit and when that is hot it's going to start cooling and I want to make sure I get it down on there all the way right away and any little binding is going to cause it to hold up and then basically not go on all the way like I want it to now you certainly can take and put the pinyon into the freezer it will also shrink the diameter it will definitely help on the assembly and so the the cold shaft in the hot bearing it'll increase that clearance and everything will just glide down and then you just let it room-temperature back to to normal ambient and it'll cinch itself on there nicely while we're waiting for that to heat up on to the ring gear in the carrier now this is a brand new ring gear one of the things they always advise is to run a small file over this area this is the surface it's going to set whoops set against here you want to make sure there's no burrs no no nothing on here because you want that to sit down flat I'm just gonna take a flat file again just making sure there's no burrs obviously this surface isn't from it has a little higher edges here but it looks pretty good now obviously the ring gear goes in this direction bring it down what I like to do is take a one of the screws put it up in here because once it's pushed down there's a slight bit of interference or at least location to this and it sometimes they don't like to rotate once they're on that location so to make things easier and what I'm trying to accomplish is lining up the bolt holes too is enough to locate it around the radius so that pushed down in there in a now it's located on center to the center of the the rotation of the bearings okay now I am going to just tighten these up just so they're snug and I can see that we're gonna have fun with these bolts these are not gonna work you can see that the recess in the carrier is not quite large enough in diameter for my socket to fit down in there nice and tight but the head of the bolt is just proud enough to grab it and there are no washers that go with this the bolts all get locked itíd put lock tight on the threads and then and then thread in and then of course torque - I think it's 60 foot-pounds so we'll see if we have an issue there if we do what Wow all we'll need to do is get some different bolts it's not the end of the world it'll just be one more day that it sits on the rack and waits so this morning we got some fresh bolts and you can see these are quite a bit different head size these AR peas will go in here and clear I'll have plenty of room as far as the socket is concerned I'm surprised that the shoulder is a little bit smaller but at the same time this is what ARP does I'm sure they're right so now let's get some Loctite on these bolts and get this buttoned up torque on these is according to AR peas number is 55 foot-pounds now to get this torque down I'm not gonna be able to hold this at 55 foot pounds so I'm gonna take it over and set it in the vise you can see I put some towels on here kind of protect some things and I'm gonna use the windows a little bit to hold it and I'm not gonna pinch this tight that's just gonna be snug enough to hold it from spinning now I still use this you take these 255 foot-pounds I'm gonna increment up I'm gonna go to 30 and then 55 and use a star pattern pattern to pull the gear up so alternate around our ring gears now installed onto the carrier this is ready to go into the axle housing now last thing I need to do is get the bearing out of the toaster oven there and get it put on to the pinion there just like it's supposed to go just like that that simple put it on there you notice I grabbed it and moved it as fast as I could because as it's coming from here to there its cooling it only needs to change by about mm and it will not go on that shaft without a press but when I dropped it down you can hear it Clank I know it's seated at the very end I'm gonna let this cool and then we're gonna get it into the eggs into the axle okay so we're all ready to install the pinion I'm gonna put a little oil a little more oil than what I already have on here and that way when it's installed it already has some lube on the bearings themselves and also I'm going to be checking the torque that requires to rotate the pinion when it's installed that needs to be on new bearings is like 25 inch pounds so that's why I want to make sure I got Lube on there so it's it rotates smoothly so I know I need to put the front bearing in first and then the seal that captures everything now I have a high-tech block of wood here that's gonna work perfectly hopefully without splitting because you want to drive the seal evenly if at all possible here we wanted to highlight a little issue here we ran into directly with the seal and in 69 there's actually two seals and they carried it on for X amount of years but there was two seals one for the truck and one for the car in the snout on the housing slightly different that's why there was two different seals and the inset where the sealing surface is at now what's happened is the kargh seal for whatever reason has been discontinued and the only one available now as the truck seal typically speaking your pinion bearing here should be free-floating by about say at least a quarter inch or eighth inch somewhere in that ballpark and what I caught was this doesn't have any one the seal is installed fully like it's supposed to be where this surface hits the surface of the housing now the sealing surface to the yoke is right up here and at this point that's in the chamfer so I can install this everything will go together but this will leak fluid like crazy kind of like it's witnessed up here so to come over here in the workbench I've done a little homework I've come up with these three different seals that are of three different manufacturers this one happened to be in our initial kit and these are two other aftermarket emkin in a SKF but the point is is all three of these are slightly different but none of them will actually function the way they're supposed to if fully installed and you can see a good witness of that so here's your sealing surface on the yoke and it has this chamfer that's roughly an eighth of an inch if I put this on here I'll flip this over so you can see it that sealing surface the ridge and I'll pull back the ridge it actually seals is not on the large diameter of the yoke it's still riding on the chamfered edge so yes it'll go on there it has a marginal seal relative to the dust side of things but not on the grease seal side this will install everything they'll go together like I showed you over in the axle but this is still gonna leak now what I found is you can do three different things you can install this and not install it fully so you would leave a gap now in my opinion that leaves for a lot of margin of error because it's easy to have it rocked inside the housing slightly the second area is you could take a piece of welding rod this happens to be a little small but the point is the same use a you know say a eighth inch welding rod bend it up and slip it over the top of this now you have a firm stop and you'll have a gap when you're done and then the third option and which I think is probably the best option is actually a solid ring I happen to machine this out of a piece of steel I had laying around and luckily I have access to a lathe and this will go in here then and act as a physical stop that will give me an eighth inch of a gap and if you can see here now my eighth inch forces that sealing ring up onto the sealing surface I'm sure somebody's out there thinking boy that sure is a hack way to install that in and you know that's probably right but at the same token it is the only way to do it because there are no seals available that that brings this sealing surface toward the yoke further they're all inset like this so the only way to do it is to short install it if you have an aftermarket housing for instance like a Moser or a strange they've actually increased the length on that casting and that gets away with that so it's only on the stock 12-volt housings from GM that are short that needed that longer call it longer seal this way to install these correctly and make a good seal so now that we know what our problem is let's get this seal back out of the way and put our spacer in with a pressure seal [Music] say loudly our spacer and our seal fancy installer I'll get that now it actually has some float like it should and you can see I have a gap between the face of the bearing to the sealing surface problem solved alright so my gear my bearing is lubed up a little bit now I need to put the crush sleeve on this is going to maintain a preload between the bearings and now I can slip this up inside of here it will not go in all the way yet because a little bit I like to use a little of this sealer on the splines and all this is going to do is stop any kind of seepage if you will of gear lube coming up the splines okay it allows me to have some thread hanging out the nut has a kind of a crush or pinch nut on the top I still put just a pinch of blue loctite on it washer it's not quite enough not enough thread showing right now I'm just gonna take now the pinion torque is not in your traditional sense meaning torque the pinion nut to 255 foot-pounds and you're done what you're going to do is you're gonna torque this nut so it sufficiently compresses that spacer the crush lead that's in there so then you have a rotational torque of 25 to 30 inch pounds on new bearing if you have a used bearing for some reason that's going to be closer to like 15 but on new bearing your 50 or 25 to 30 so that's the the next step here you're not gonna be able to hold this by hand unless you're the Hulk himself so I picked up this $13 tool from All Star it has multiple holes in it and you see it has two square drives I'll be able to use a smaller half inch square drive just use a couple of the yoke bolts and some washers if needed I'll be able to hold this with a breaker bar and then I can get my I'm actually going to use a torque wrench up in the center of this and use them together to tighten up this nut not using an impact break your bar on there now I am gonna set this to a number just sign norm at it's gonna take at least 150 probably a whole lot more but alright breaker bar is on here I'm gonna rotate this up now obviously I can use anything on the body that's secure or anything on the car that's secure to help hold this torque or I should be able to hold it by myself well here I can run it up against the leaf spring and give me your hand with it this is going to be wobbly until you take up the slack this is like the butterfly exercise at the gym if you go to the gym this is that's what I've heard so like I said there's 150 and I still have a lot of slop now please notice that I have this up on a hoist I should not be able to move the car with the breaker bar on this yoke but if you're on a set of jack stands you better be careful okay now I have no slop however I know at least by feel that is not 25 inch pounds that's probably closer to one or two it's just barely dragon so I need to take take this part slow to go incremental turns okay now to do this you could certainly use a a clicker wrench set at 25 I happen to have the luxury of a having a digital again I'm looking for 25 to 30 and that is about 13 look at that 29 we'll take it next step now is to come to this side of things and get the carrier with the ring gear up into the hole and start setting that backlash right to left so I have a little axle here on my my bearings and I've also taken and put a little L in an R on the on the bearing head cups and the idea is they should be left with their mating bearing and at some point I'm going to drop these so we'll see it oh that's gonna roll up into your carrier spot now this is where I'm gonna take a set my lash so like I said I'm going to use these spacers I'm gonna start with the ones that were in it the factory ones set that in there slide everything all the way to the other way now this may or may not fit and that's fine if it doesn't I have a whole brand new shim packed yeah that's gonna be too tight now our bearing kit here has or our shim kit has a one bearing that's has this shoulder into it as you can see the idea behind that is now I can take and Pat my thin shims to the center put a larger shim on the outside to help protect them and as I tap this in it'll give me a a means of not booger up the thin ones so the idea here is I have so I have some shims over here and you can see I mean it doesn't take much to figure out that's a lot more than nine thousandths I'm just right now I'm just pushing everything into this bearing and and rotating the ring gear so this is certainly a educated trial-and-error meaning I'm going to take and keep adding shims to this pack until it tightens up I believe if I'm up against that one then I'm dead solid so I need a little shim over here to push this this way and you can do it from either direction so I can shim from this side to get my too rough get my lash or I could shim from this side to rough get my lash all depends on which way you want to do it so I have a little bit of a shim in here you can just see it's about a 20,000 shim between the factory one and the housing and that's gotten me pretty close that's a whole lot better what we started with now to accurately measure that you'll need a dial indicator and it's just that plunger little dial as it moves you can measure the you get a number you want to set your dial indicator on here as straight as possible meaning you're not getting some weird angle so you're not you're not hitting it here you want to hit at this perpendicular to the gears as possible and I say as possible because I only have so much room you have to measure it one way the other now I'm perpendicular to the face the tooth don't confuse that with perpendicular or tangent to the radius so with that just a quick check so I'll zero this out yes to have an even number so I'm at 20 they're putting a little light load so all I'm doing is I'm pushing I'm forcing contact to one side of the tooth surface of the ring key ring gear and the pinion as they made up and now I'm just going to the backside of that and it gives me right now I got 13,000 now after having the carrier in and out about 20 times I finally got to the point where I have my shims where I like them so what I did is I took shims all the way out got the gear in to where I had no lash I got to like mm and then I slowly incremented it that way now you have to keep the left side tight so every time you let's say you add ten thousands here you need to subtract ten thousands over here and vice versa so as I pushed it away I kept moving shims around until I got to the point where my spec is 7 to 9 for a street gear and moving this I have 8 which from a tolerance standpoint you don't get any better than that next step is going to be I'm gonna tighten these caps down a little bit more alright now I have them snugged up but I need to take and check my gear Pat or my tooth pattern to do that I use this paint right here in fact I'll paint it on right now so you just take some of this paint and this washes right off you don't have to even remove it the gear lube will law take care of it later but you paint a couple of the teeth and you're looking for the contact patch if we look through your gear assembly instructions your installation instructions it'll show you that you want to have you know the path the pattern should be centered top to bottom and kind of centered front to back but a little bit closer to the bottom then then to the top but not much that's part of that we're in that they did at the factory so let's get this out of the way like I said I want to put just a pinch more torque on here and I'm not final I'm not doing my final assembly I'm still doing mock-up because I'm still gonna take the I still need to take pull the carrier out and I'll add ten thousands more shim here then I have here to put that pre load on the bearing pack alright with that come up on this side and I'm just spinning the gear hold a little pressure on there well you can start to see the pattern I'm getting so the pattern is is on the front third of the tooth but you see it stops way down here at the edge it's fairly centered it looks pretty good it's not too tall it doesn't seem to be too short but I'm going to double-check that to the to the other and you can also see the mating surface here now the pinion depth if that's dead perfect and your and your gear lash is set of course gear lash is just relative to a little bit so the gear doesn't bind your pinion death is really what sets this tooth pattern and at this point it doesn't look too terribly bad I don't see that it's off obviously I can't put true torque on it so I can't get it to flatten out way back in here but you can see where the pattern looks good through here it's not going to grow towards the front it's only gonna grow towards the back all right so to make a little clearer here's the directions and here's what the correct load pattern looks like now this is the inside this is the outside so let's flip it over so we can see it right alright so you can see I'm on the this would be the drive side see it's fairly it's pushed towards the front but not all the way the contact isn't as long as it shows in that picture but we're certainly in the the collet B if you divide this in the fifths you're in your front fifth so to speak not directly in half and not really 1/3 so it's shifted just a little bit towards the front now if you look at the coach side of the gear right here see we're pretty good we're it's nice and tight this is probably a good one to look at so you got it it's almost centered like it like it shows in this diagram okay the biggest thing for wine is certainly setting the pinion depth correct we have that pinion depth right on this is just kind of a double check to make sure something's just not crazy I don't know you miss measured it I guess so I think our depth and tooth pattern looks pretty good you can see even in the inside as it as it's hitting the opinion you know what that looks like in there that should also have a nice long pattern it shouldn't be all the way to the toe and not all the way to the heel at this point we're ready to pull the caps back off real quick put a 10,000 shim in here and that's just to preload those bearings the carrier bearings and then we'll put the caps on for the final time torque it down nice and tight I'll put 30 on the top 130 on the bottom on the same thing here and then I'll do 50 so they'll torque down even all right now after you have everything all torque down rotate your pinion a couple times all the way around and and then throw your dowel indicator on there one last time oh it's perfect right on the money so now simply take the axles put them right back in like you took them out line it up with the spline now I don't have the cross pin out so they're not going to go in all the way yet this side same thing with this cross bolt in here I'm gonna pull this out now as you rotate the carrier you have to be a little careful and we'll probably have to persuade this a little bit because it's from the factory alright so there's the pin out of the way just like the factory one was now I'm just gonna reach over and push the axles in all the way take my c-clip a little magnet and reach that up into there they have to work things around a little bit now that's up in its slot pull the axle back out that one's installed the same thing over in this end put this back in you can bring this in from the top or the bottom doesn't matter the key is you have to line this hole up with the hole in the case I'm gonna go from the top since that's run angle that now we may have to fight this just a little bit to line that pin back up cuz I might not have got that quite right if you do just take and push it back and forth until you get it right it's no big deal don't take and slam a ham right here this bolt has a little star washer on it to hold the torque this does not get torqued a ton that's it's in the inch pounds range it's a small bolt but if you forget to torque it and it comes out it will Jam against here and you'll have a bad day that's good there now if we look at our axle ends both axles will be turning now so now does our left side turn when our right sides turning that answer should be yes and we no longer will have a one wheel peel okay put the cover back on I'm gonna put a little silicone on the seal this is a cork seal with the steel Center these are the best ones to use the cover will only go on one way eyebrow up and then locate your holes these bolts are all exactly the same except for one the one is one's a little bit longer and usually has a washer rotating washer on it and that goes clear up here in this spot the reason this is longer because you have a tab that goes on over top of the cover as well so it adds a little bit of thickness and they gave it a little bit longer bolt to hold it down so right here alright so we're gonna get this buttoned up we're gonna put fluid in it the fluid fills over here on this side fill it up until it starts coming back out of that hole and put our brake drums back on wheels back down I guess before we throw wheels on this and put it on the ground we probably should put the drive shaft back into now we're gonna run this for about 20 miles nice and easy meaning just normal type of driving and then we're gonna let it cool back to ambient the reason you're doing that is your seating parts just like breaking in an engine so tomorrow we'll leave it set for 24 hours tomorrow then we'll take it for a a good spin if you know what I mean so the other side of changing your ears you're probably going to change your speedometer reading so I'm using the GPS here and stuff my phone and it reads above we're running about 55 miles an hour but my speedometer now reads at about 68 it wasn't right before it's certainly not gonna get any better right now but we may need to change the rear tires as it is because the ones around us is pretty small so when you're finally done you know what gear you have you know your height and your tire then make your gear change in your speedometer it's really simple just in the tail shaft of the transmission it doesn't matter if it's an automatic or manual just pull it out put a new one in and that'll recalibrate your speedometer tomorrow morning we'll hop in this and see if we fix that one wheel peel issue [Music] let's see if we fix that broken leg alright looks like we fixed that one wheel peel and they're fresh gear is in so this projects are wrapped however if you have any questions please leave them in the comments we'll do the best we can answer them click and subscribe most importantly get out there enjoy the road [Music] whoo

Channel: Hagerty

Views: 819,598

Keywords: Hagerty, Classic Car, Classic Cars, Hagerty Drivers Club, DIY, How to, mechanic, garage, do it yourself, learn, GM, General motors, posi, positraction, LSD, limited slip differential, peel out, burn out, one wheel peel, muscle car, pony car, Camaro, SS, 1969, gear, rear differential, rear diff, hot rod, hotrod, traction, traction control, skid out

Id: DRWhDRIaR6w

Length: 65min 54sec (3954 seconds)

Published: Wed May 22 2019

Reddit Comments

[u/gimpwiz]

Love their videos. Long and informative.