How We Fix GM Transmission Failure (6L80 & 6L90)

foreign so this is a video I've been looking forward to making uh because it's something I'm seeing a lot of in the shop it covers a wide range of GM vehicles starting in 2008 on the Cadillac Escalades Tahoes uh it was the first introduction of the GM six-speed transmission and they've used it all the way up to 2018 you can find this in virtually every GM truck application uh the transmission is called the 6l80 6l90 series transmission and what I'm really excited to show you guys is not only what fails in these Transmissions but really what we're doing to address the issues because it these these are some very dramatic failures but also the fixes are some real-time fixes that um you'll be able to see here on camera so I'll go ahead and start taking this transmission apart and first off going through the points of failure why they fail and then what we're doing to fix them so what we're going to show you here today is a demonstration of what a pan looks like when your transmission has failed so you're not what you're not going to be able to smell is the horrendous smell of the fluid right now but it smells bad also what we've got is a large amount of sediment built up in the pan this is clutch material and on our magnet you can see it's all spiky that's a lot of metallic material there right this is a transmission that's experienced a pretty severe internal failure okay so we got this transmission apart um I didn't take it fully apart but I took it apart to the points of main failure here uh right here we got the one two three four five reverse drum uh it's a very high point of failure and we've got the pump assembly here so now I'll go through each one of these um and then explain where the actual failure typically starts um on this one two three four five reverse drum if you look in here closely this component here is what's called friction or Fusion welded that's when we take two components and we rub them very fast and hard together and they actually fuse together that that is a form of welding what we do to correct this issue because it's this area is actually known to crack and the common complaint we get with this is that it loses Drive shortly after or you have no drive because it's completely broken now what we do is we've engineered a solution working with a machine shop where we Groove out this area and put a bead weld in there this not only strengthens the area but it also corrects the issue from ever happening again foreign [Music] take a look at our pump assembly and we flip this stator up when our torque converter fails we get a bunch of material that passes through because this is the first area connection if you take a look here we got we got a bunch of grooves here um this in this one the torque converter failure has caused our pump to fail so this is another high point of failure that we need to look at when we're working on these units moving on here we're going to look at our torque converters now this is the area I really wanted to focus on this is a torque converter here for anyone who hasn't seen one this is complete for the sake of this demonstration I actually had some of these cut open so if we we take a look here we have two bases these are stock bases okay this would be this guy right here the back section of this torque converter this is called the torque converter base you can see it looks very similar on this one just not the other half of it so why does this happen why did these things fail if we take a look at these we see three areas where they've been quite hot okay let the camera zoom in on that now if we flip them over they correspond to the pads on the back side now what what happens in the factory when these things are assembled first of all let's bear in mind that these things are made from a pretty cheap steel okay it's just a stamped steel now when we with with the stamped steel why is that important is when we weld these lugs onto the back we create this heating now what happens when we heat metal it actually hardens in that area now we have three areas that are hardened versus the rest of the surface now this causes an uneven surface and causes surface flexing when we apply the torque converter this is the result of uneven wear over time we see it's completely scored there would have been a clutch material here a disc that would have gone on here and the lining completely comes off because you get uneven application and we get failure and that material passes into the transmission and that's typically the result of what we get after so I've actually got two of them here to show how common this is you know my my local torque converter guy could probably send me a bunch of these that'll just show me how many of these actually fail so what do we do about this right here is the solution so this is what's called a Billet base okay all of our torque converters that are built are all of our 6l86 l90s that are built here are built with one of these billet-based torque converters what's the difference in these you can't pick this up or feel this to the video but it's about twice as heavy as the original stock base now if we look at the back side the pads are actually machined into the surface that means there's no surface hardening we have an even hardness through the whole material it's also made from a much better quality Steel and much more rigid so there's no flexing this addresses all three points of failure that exist in the factory base and we don't see these things failing at the same rate as the factory one so we've taken you through some of the key points of failure on a 6l's 86 L90 series transmission uh we didn't do a complete tear down we can do that on a later video but I wanted to address some of the key points of failure and what we're seeing uh coming through our doors quite often so if you are an owner of a truck that might have this application you know anywhere from as I've said from 2008 through 2018 that's a 10-year period and you're noticing some of the symptoms that I've mentioned um come on in uh you know if your vehicle is still drivable of course and uh we'll be happy to look at that for you because these might be some of the things that are going on with your transmission foreign

Channel: National Transmission

Views: 126,369

Keywords: Transmission Failure, GM, 6L80, 6L90, Cadillac Escalade, Cadillac STS, Chevrolet Avalanche, Chevrolet Silverado, Chevrolet Suburban, Chevrolet Tahoe, GMC Sierra, GMC Yukon, Chevy, Hummer H2, Chevrolet Express, GMC Savana, Chevrolet Corvette, Chevrolet Camaro

Id: CnLOi66dcho

Length: 7min 0sec (420 seconds)

Published: Fri Nov 11 2022