Common GM Truck and SUV Transfer Case Problems

In this video, we're going to be going over some common problems on a GM transfer case. Now, if you have a two-wheel-drive truck, you're not going to have one of these. Now, what this actually does is it takes the power from the engine, going through the transmission, and then it goes through the transfer case. It's gonna power the rear wheels first. Those are going to be powered all the time until you select on the selector switch, whether you want to be in four-wheel-drive high or four-wheel-drive low, then it's going to transfer power to this driveshaft to the front differential. So, that's how you get your four-wheel-drive, and on some vehicles all-wheel-drive. And there's some common problems on this, so we're going to go over those problems. So, we're going to start with one common issue. Now, this vehicle has a seal right here and it is leaking, and it's leaking transmission fluid. The fluid from the transmission can come right up to this seal. And there's a seal actually inside the transfer case, the input seal, that's supposed to keep transmission fluid from getting into the transfer case. Sometimes if that seal goes bad, it empties a lot of the transmission fluid into the transfer case, and then when you go to pull the fill plug, if you put a drain bucket underneath and you pull this fill plug, a lot of fluid comes out of there. If you see that, then you know that internal or that input seal is bad and that needs to be replaced. The only way to replace that is you have to pull the transfer case out, replace the seal, and then put it back in.

Another common problem is this case. Sometimes you will have a pinhole in any area like right here or right here. I have personally actually seen it with the pinhole on the top of the case, but there is a fluid pump inside the case and the fluid pump will vibrate back and forth and eventually wear out the back of the case. So, what you need to do is replace this case half. When you do that, you're going to have to pull the whole transfer case out, put it on the bench, pull the case half off, and replace that and you should be good to go. All right. So, you may have a leak coming from the tail shaft seal. Pretty easy repair. You just pull the driveshaft down, pull the old tail shaft seal out, put the new one in. There's a little hole right there. That's a little drain hole. You want to put that at the bottom. You don't want that at the top. So, after you replace that, you drive down the road and you notice it's leaking again. Well, maybe it wasn't that tail shaft seal. There's a bushing in here, and sometimes those bushings wear out. And after you replace that seal, it's still leaking, you actually needed that bushing. So, you can replace that bushing separately or you just get the hole back case out. And sometimes the encoder motors fail internally and they'll have a problem. Although most of the time it's just the sensor that's inside the encoder motor, and you can replace that sensor separately. You pull the encoder motor off. You have to pull the front driveshaft off first, pull the encoder motor off, disconnect the electrical connector, take the encoder motor apart. There is some screws. And when you replace that sensor, you put it back together, put it back on. You should be good to go. That sensor will give you a check engine light or a light to do with the four-wheel-drive. There'll be a fault in the four-wheel-drive system.

So, those are common problems with the transfer case on a GM vehicle. We sell a lot of those components at 1aauto.com. Check out the site. If you enjoyed this video, make sure you subscribe to our channel, ring the bell, turn on all notifications so you don't miss any of our videos.