How a Differential Works

today I'm going to show you what's inside of the differential and how it works to make the wheels turn on your car so here we are on a two vehicle we have the drive shaft where it connects to the universal joint to the rear differential so at the rear subframe removed on the vehicle we have a very clear look at how the differential is housed in the rear subframe of the CV axle is actually bolted up to the hub here so I'm just gonna remove it with a giant socket now it'll separate the CV X and we just have the differential attached to the subframe so here we've got the differential removed from the vehicle at the sides here we have where the half shafts will bolt up to to turn either rear wheel and at the front here we have the input where the drive shaft would turn the differential the differential is responsible for allowing a difference in wheel speeds between the right side and the left side wheel when taking a corner now when the vehicle is moving in a straight direction both wheels are turning in the same direction at the same speed now when input is supplied from the transmission to the pinion gear here you can see that both of the wheels are moving exactly the same amount however when the vehicle is taking a corner the inside wheel is going to slow down and the differential is going to allow a difference in wheel speeds between the inside wheel and the outside wheel while the transmission is still providing power to it so it can take that corner now if you look closely both of these are moving at the same speed however when the inside wheel slows down the outside wheel tends to speed up for the same amount of input action now in order to take a closer look at what's going on inside of here we're gonna have to drain all the oil and take a look inside of this casing now the gear oil inside of here is pretty thick so I'm going to remove that drain plug and then I'm going to slowly lift the differential over to drain out that oil at the pinion I'm just going to back off this not but the puller on this flange here I'm gonna give it a go next I'm gonna remove all the bolts to remove the differential cover and remove that cover now inside of the cover we have a magnetic drain plug to capture any particles floating around we've also got a breather over here that goes through this valve on the outside now sometimes this valve or the hose connected to it could get clogged and that will cause you to blow out some of the seals now things are gonna get pretty oily so I'm just gonna use my brother's old undershirt here to wipe down everything so we could have a closer look so here we've got an overall exploded parts diagram of this rear differential we've got the pinion gear here which makes the drive here the drive gear is then bolted to the differential case now inside of that case we have this little pin here where we have the two spider gears that pivot about it and doesn't reconnect with the two side gears which go out to each axle we've also got the differential housing and its associated rear and side seals and the rear pan cover now here we have a nice clear look at the guts of this differential on the side here we have the two main bearings that the guts of the differential right up against inside of this housing not as big gear as the drive gear and way inside at the back there is the pinion gear that drives it a further inside of this housing we have the four small differential or spider gear now as I rotate the input shaft of the pinion you'll see that this drive gear also rotates and a rotates at the same speed as this carrier inside the carrier will see that these gears are locked and they're not rotating relative to each other which means that the right side and left side wheels are moving at the same speed in the same direction and this would be ideal if the vehicle is moving straight forward now let's say I'm rotating the input shaft but I lock up one of these wheels you'll see that the spider gears on the inside are now moving relative to each other and that's transferring all of the power from this ring gear to the one other wheel that doesn't have anything holding it likewise if I lock up the pinion as if the vehicle is in park and I rotate the right side wheel you'll see that the ring gear does not move and only the differential gears on the inside move and that allows the other wheel to turn in the opposite direction now this design is known as an open differential and its main disadvantage is traction for example if I'm rotating the pinion gear and I hit a patch of ice on this side well the energy from the engine has a tendency to go through the lease path of resistance and it's just going to turn and slip this wheel here well this one remains stationary therefore you're going to be stuck on that ice during a one wheel burnout while the wheel that has traction is not going to get any torque now there are a number of ways in order to overcome this disadvantage the first of which is to use a limited slip differential which has a series of clutches and viscous fluids to limit the difference in torque between these two wheels but still allow a tiny bit of slip so you can take corners now a limited slip differential uses two clutches on the two side gears to separate the gears from the shaft himself and go to the CV shaft now the clutches have these tabs on it then lock into the differential casing as well as these teeth on it they lock into the shaft itself now driving straight the spring is gonna put a lot of pressure on these clutches and cause them to lock which is going to essentially create a locked solid axle however if there's a small difference in wheel speed such as taking a corner it will easily overcome that spring pressure and allow a little bit of slip in these clutches so you can take that turn there's also the locking differential for low speeds which will completely lock all these gears together allowing them to rotate and get you out of that icicle and then there's a brake actuated traction control which will clamp the brake down on this side increasing its resistance the energy will then come through over here to the wheel that has traction as its path of least resistance and get you out of that puddle so now I'm going to separate these side flanges here and the one on this side now this side flange is what connects the CV shaft to the spider gears inside of here next up I'm going to remove the main bearing bolts and then now we can separate the bearing caps and one on this side I'm just going to use my seal puller and remove the seal here just gonna remove this differential gear from the housing assembly here things are about to get really greasy and service can use my brother's old sock here to wipe it off here we have the differential remove from the housing and you can see the small little spiral gears on the inside there that are free spinning now it's important to note that the two gears on the outside here do not attach to this housing directly as a matter of fact the flange will bypass the housing through this bearing over here and connect to this little gear on the outside the housing itself attaches to the differential casing through this bearing over here now the bearing itself has a conical surface area which is good for rotating but it also allows it to absorb any axial forces that come because this ring gear is cut on an angle now in order to remove this pinion gear I'm gonna use a special press and now I can reach in and remove the pinion gear note the pinion get removed you could see it's got a special kind of swirled cut on it as well as on the ring gear and that's to make things a little bit more quiet but also to transfer more power you can see just how the interlock over here and it will rotate that ring gear now you'll see the pinion gears considerably smaller than the ring gear and that's gonna give you a torque multiplication now the ratio between the opinion gear and the large gear is called the final drive ratio and ultimately determines your acceleration versus top speed trade-off and that final drive ratio is determined by the numb of teeth and a large gear divided by the number of teeth on a small gear here I've got the front differential of a 2001 Corolla took apart a few years ago this used to sit inside the transmission and didn't have a separate casing like this one this one here is the one from the g35 you could see how the spider gears are much thicker and chunkier compared to the ones on these smaller Corolla but the overall ring gear size is about the same diameter now I'm just gonna remove all these bolts I can actually remove this ring gear here just like that now besides completely blowing up the differential casing also has a few other failure points including the seals on the sides and at the pinion that could leak we've got these bearings here that could wear out causing noise or knocking we've also got these bushings here that could wear out causing a loss of power distribution under hard acceleration and that's pretty much all the components that go into making the differential on your car work make sure you follow me on Instagram for more behind-the-scenes footage and subscribe for more videos just like this one however when there's a difference in wheel speed between the left and the right side [Music] you

Channel: speedkar99

Views: 1,158,351

Keywords: DIFFERENTIAL, DIFFERENCE, gear, pinion, transmission, tooth, final, drive, ratio, speed, acceleration, locking, limited, slip, drifting, welded, bearing, bushing, seal, leak, fluid, how, works, inside, automobile, clutch, viscous, oil, science, calculation, torsen, open, traction, control, torque, vectoring, drivetrain, mechanical, CV, axle, turn, rotate, mechanic, dana, ZF, Aisin, nissan, g35, infiniti, g37, 350z, RWD, FWD, AWD, jasper, converter, CVT, Allison, Borg warner, Denso, jatco, engineer, spider, ring, carrier, planetary, LSD, wheel, ABS, brake

Id: e-VvLw7pjk0

Length: 7min 50sec (470 seconds)

Published: Mon Dec 16 2019