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Burnt Fluid Hard to Move Might Be Time to Swap the Transmission

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Burnt Fluid Hard to Move Might Be Time to Swap the Transmission

Created on: 2020-12-02

Andy guides you through the process of removing the old transmission and installing a replacement for the GM GMT800 truck and SUV platform

Installation Video
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What's up, guys? I'm Andy from 1A Auto. Now, we have this 2005 Chevy Tahoe that's having some problems with the transmission. Whenever you shift the vehicle into reverse, it's not gonna move. You rev it a little bit, it still really doesn't move, you really gotta push it in reverse. And then most of the forward gears work. Sometimes first gear isn't working too well. The transmission fluid is severely burnt. It smells horrible. So, the internal damage has already been done to the transmission. So, in this video, we're gonna take the transmission out and put a new transmission in it. Now, the procedure for this Chevy is gonna be the same as on a GMC or a Cadillac, in the same platform. It'll also be the same as on a truck.

We're gonna disconnect the negative terminal on the battery. Use an 8-millimeter wrench. We're gonna slide it out of the way. Now I'm just gonna remove the dipstick. Just slide that up and out of the way. Now remove this shield. Use a 15-millimeter socket. Take these four bolts out. Make sure you support the shield once you get the last one out. Now, before I take the driveshaft off, I am gonna use a marker and just mark where the position of the driveshaft is, so that when I put this back in, it's gonna be installed in the exact location. That'll prevent any unnecessary vibrations that you may have caused. Now I'll take a 11-millimeter wrench and loosen up these bolts on the caps. Do the same on the back side, and take those off. Now take a pry bar in between the yoke and the U-joint, and just pry the driveshaft toward the front of the vehicle, and just grab the driveshaft and slide it out.

Now we need to remove the front driveshaft. On this one, someone's put a wire tie for this clamp right here. Normally, you'd have a band clamp like this, and you're gonna either need to cut it off or just try to pry it off and get that out. Here, I'm just gonna cut this off. Just use some side cutters. Slide that off. Then you can use a screwdriver, and just pry this boot over, just like that, and I can sit like that. That's fine. And then at the front of the driveshaft, we're gonna mark, again, just so we don't end up with vibrations afterwards. Put it back together the same way you took it apart. I'm gonna take a pry bar and just go in between the yoke and the driveshaft, and use the 11-millimeter wrench, and loosen these bolts up. Now I'm gonna take a pry bar, and just like the rear driveshaft, just pry this back, and then you're gonna slide this forward. You might have to pop that boot off again. And slide it forward just like that.

We have to disconnect all the wires that go to the transfer case. This is a wire that goes to the encoder motor right here. I'm just gonna cut these wire ties, and see what's right here. Slide those retainers out. There's a connector right behind here. Slide that connector out, right there. Disconnect the connector to the encoder motor right here, and slide that out. And this connector right here, that's for a speed sensor. Slide that off. Another speed sensor connector right here. Slide that off. And just make sure nothing's connected to the top. There should be retainers holding these all on.

Now I'm gonna use a transmission jack and support the transmission. Take out a 15-millimeter socket and take these two nuts off that go to the mount. I'm just gonna raise up the transmission a little bit, just to make sure there's no tension on this crossmember. And then I'm gonna take these two bolts out, and the nuts are on the opposite side. And use a 21-millimeter socket and a 21-millimeter wrench on the other side. Now, just hold the crossmember, pull those bolts out, and slide it down. And just take this mount off. Use a 15-millimeter socket. Take that bolt out, and same on the other side. Now, there is six nuts that are holding the transfer case attached to the adapter. Use a 15-millimeter wrench, and take these nuts off, and just be careful when you get to the last one. Keep in mind that there is fluid in between the adapter and the transfer case, so you wanna put a drain bucket underneath when you separate this. And to get the top nuts, I use a wrench that I actually bent just for this, so that I can reach in there. It makes it a lot easier.

On top of the transfer case, there is a hose, like a breather tube. You need to take that off. Try not to break that 90-degree elbow, just like that. Just make sure everything else is disconnected from up top, and it looks good. All right. Now we need to remove the transfer case, take that nut off. I'm gonna slide it back, and then we need to tip the front of the transfer case down. It's a good idea to have a partner just nearby, to help support you in case something falls. All right. So good. All right. Now we're coming down. All right. We need to remove the exhaust. So, before that, I need to disconnect the O2 sensors. There's four of them. So, there's a connector right here. Just disconnect that. And then there is a wire hold down. Just slide this off or use a trim tool and just pull that out. So, you can do that with the other three.

Now I need to take the nuts out of this flange right here. Just use a 15-millimeter socket. I'm gonna do this on both sides. I'm just gonna leave one of these nuts on here, so that when I disconnect the back side of the exhaust, that this doesn't just fall. Now, there should be a flange right here where you take two more nuts off, or bolts, but this vehicle has been modified and welded. So, I actually have to take the pipe off right here, and just move that down. I'm just gonna slide the muffler off on this one. You normally don't have to take the muffler off. There we go. Now, I'll take that nut off and slide the exhaust down, and just slide it out.

Now I'm gonna remove the starter. I'm gonna use a 13-millimeter socket, take those two bolts out. And now slide the starter back. All right. Just get that out of the way. Now, you can either take these wires off, disconnect it, and pull the starter completely out of the way, or you can just find a place where it just sits, and just leave it there. It doesn't matter. We can just prop it right here, just like that. It's out of the way. You just need to be able to access the torque converter bolts. There's a cover right here, a plastic cover. Just use a 10-millimeter socket, take this bolt out. And then you can remove that cover. If you have a shield right here, you wanna remove that. And then I'm gonna remove this shield as well. I'm gonna use a 15-millimeter socket, and slide that down.

So, I need to be able to access the crank pulley to put a socket on the crank bolt. I'm gonna use a 24-millimeter socket and a breaker bar. This way, I can crank the engine, just turn it slightly. Then I can move the bolt for the torque converter, so I can access it better. So, you only wanna go clockwise. You really don't wanna go counterclockwise in there. All right. Now I'm gonna take those bolts out, just one at a time. Use a 15-millimeter socket. There we go. Just don't drop it. And rotate the engine until you see the next one. There we go. Once you get the last torque converter bolt out, you wanna reach around the flywheel and just see if you can move the torque converter. Go side to side. And you kind of wanna push it back towards the transmission a little bit. Now I wanna start disconnecting anything on the sides of the transmission, so the shifter cable. Take a straight blade screwdriver. Just pry this off a little bit. There's a little lock right here. And then just squeeze this. Just use some needle nose. And set that aside.

And where the connector is for the range selector switch. Slide this down. That's disconnected. And there should be a bolt holding that bracket on. That's broken. It looks like that's all disconnected. Take this heat shield off. Use a 10-millimeter socket. There's two bolts. Take those out. Now disconnect this connector right here. This connects the electrical components to the transmission. You just squeeze these. And there's a vacuum hose right here. Just gonna slide this off, just like that. It's still attached up top of the transmission. And these two transmission cooler lines, to take these covers off. And I'll use a pick, take that clip off. Yeah. Just take that clip off like that, and take the other one off as well, and then you can pull the transmission lines straight out towards the passenger side of the vehicle. There we go. Pop them off. Some fluid may come out.

Now, you're gonna need a really long extension. I'm gonna use a 13-millimeter swivel socket, and I'm gonna go right through here, and there's gonna be a nut that I have to take off for the dipstick tube. And now I'm gonna push the dipstick tube up. I'll just use a pry bar and just slide this up a little bit. We can just take the pry bar and just get under this lip, tap it up a little bit. You just need to get the dipstick tube just up enough so that we can take that bolt out up top. So that looks good right there. Now, there's a bracket on the top of the transmission, right at the top of the bell housing. You need that 13-millimeter swivel socket again. Then I'm just gonna use a hook and try to grab the bottom of it, and just slide it back, just like that. As long as that bracket isn't in your way, you can either leave it there, or you can try to pull it down. And there's one more bracket that has a 13-millimeter nut on. Just use the long extension, take that nut off. And then we're gonna have to slide that bracket off because we'll have to take that stud up, and slide that out of the way. Now I'll start with this bolt right here. Use a 15-millimeter socket, start taking those out. While I'm right here, do this one as well. And there should be one right there. This vehicle doesn't have one there. And the two on the side.

Put a strap around the transmission, just to secure it to the transmission jack. There is some different setups that you can use that always have fingers that hold that on. Using a strap's always a good idea, just to make sure your transmission's well supported. Now, on the bottom two, these are the two last bolts that are holding the bell housing on. Take those off. Use a 15-millimeter. There's a little cover right here where I can be able to pry in here a little bit better. Take this cover off, 10-millimeter, and just slide that out of the way. Now I need to take a pry bar. And be careful of the flywheel. But I'm just gonna pry in between here a little bit, just to see if it's even loose. Not really. Just pry in here a little bit. Try to loosen this up. Just do a little bit at a time. Just make sure you got all the bolts out, but just work it slowly. You don't wanna break anything. And pry on the other side a little bit. There we go. It's released right there. There we go. Almost there. There we go. Now it's loose. And drop it down slowly. Just make sure nothing's stuck on it. Now, I'm gonna hold the dipstick up out of the way while I lower this. That's good. And then I can just pull the dipstick out now. Just remember, when we're going back in, we're gonna have to slide this in when the transmission's about that level. And everything's clear. Drop it down.

All right. Before we put the transmission back up, there's a couple things we wanna prepare. The gasket that goes on this adapter, you wanna clean that up. I just took a razor blade. Be careful, if you're using a sanding disc, you don't want to sand this down. You don't wanna change the machined surface of that, because that's gonna cause a leak. So, just be careful with that. And where these fittings go, I wanna...just to make it easier, I'm just gonna put these clips in. It's easier to do it now while this is down. That looks good. And then where these guide pins are, you wanna clean those holes out with a wire brush on both sides, and same with the guide pins themselves. I just used a wire brush on those, and I did put a little anti-seize on them, just in case, for future removal.

Now, another thing, with the flywheel, there is one of these holes that is not elongated, or it's not a complete circle, and that's, like, the keyway hole. So you wanna move that to be the first hole that you put the torque converter bolt in. So I am gonna spin the flywheel so that is in this position right here. So, just do that. Just turn the crank. And that's good right about there. That way, that the hole is centered, the torque converter is centered, you could actually torque that bolt down, and then when you go to turn the torque converter, these holes will definitely line up with the spots on the torque converter. And just look at the torque converter. Make sure the torque converter is all the way pushed in. If it's pushed out a little bit, and you go to put this together, and as you're putting it together, if you push down too hard, you definitely don't wanna put two bolts in and suck the transmission to the engine, because you could potentially damage the pump on the transmission.

All right. Now, this looks good. Now I'll start raising it up. I can connect this hose right here. Just slide that in position. Just take a look at this bracket. When this goes all the way up, it's gonna be hard to see, but this bracket is gonna go on there once we put the stud through. And then the dipstick tube, just remember, get that in that area before we go all the way up with it, and get that lined up a little bit. And there we go. That went together pretty easy. So, that looks like it's almost all the way down. Cleaning up those guide pins really helped, so if you're struggling with that, just back it off, clean up those guide pins, and it should slide right in place. And then make sure your torque converter can spin. And, yep, it can, so that's good. All right.

So, check this bracket up top. Make sure it's not in between the engine and the transmission bell housing. Then we can start putting these bolts in, these stud bolts. I'll get the two sides started, on both sides. All right. Now, making sure that transmission's completely close to the engine block, and tighten these down. All right. Now I'm gonna get this top bolt in. Just move that bracket that's connected to these hoses to the side, and this is a little bit tricky, but just get that to line up. Started by hand, and then you can tighten it right down. And after you get all those stud bolts in, put these two bottom ones in. These ones are not the stud type, just regular bolts. And tighten these down. Now that I got all those in, now I can line these brackets up on those studs. Just slide that in position, and get these 13-millimeter nuts started. All right. And slide the dipstick down into position. It's a good idea to replace that seal. Just pop it out, pop a new seal in, and get the nut lined up.

Now I got the torque converter lined up with the bolt hole, and I already got the indexed hole on the flywheel moved over, and I'm just gonna take the bolt, take a little threadlock adhesive, put it on those bolts, and get this one started. Just try to wiggle the torque converter closer, so that it's flush with the flywheel. It's not the easiest thing to do. All right. That seems pretty good. And tighten that bolt down. That's good. And then I'm gonna do the same with the other ones. Just rotate the crank, and next, we're gonna get the starter ready to go back in. Just take this cover. Put that right there. Get the 10-millimeter bolt, and snug that down. That's good. And line the starter back up. If you've disconnected the wires, connect the wires back. Take the bolts, get those started, and tighten those up. Now we can put this cover on. Just slide that in position, and put the 10-millimeter bolt in, and tighten it down. And if you took this cover off, just put this cover back on. There we go. And slide the transmission cooler lines back in. Just lock them in place. Once they lock in, then take these little covers and just slide it over. That's just gonna keep the clip on. And take this electrical connector and plug that in. It goes right there. Line it up. Lock it in place.

Now everything's all set on this side, so we can put this shield back up, and put those two bolts in. Now we can get everything buttoned up on this side. Just take this connector. Line this up. Lock it in place. There is a little lock. Oh, this is broken, but normally, slide that in there, and line this bracket up here, snug that down. It's an 8-millimeter. That's good. Now slide this shifter cable right between here. Lock that in place, and then over on the lever, just like that. And put this clip on, and that just holds the cable in place. It's good. And I'm just gonna replace this donut seal before we put the exhaust up. Just grab it. Just slides off like that. Take the new seal, and just slide it in position. And this is a different type seal. Just replace that one as well, just like that.

There we go. And that's lined up there. Looks good. All right. Now get a couple of the nuts lined up. If you're doing this, you probably have the flange right here. This vehicle doesn't have that flange, so I'm just gonna tighten up the rest of the exhaust. Now we're gonna tighten the bolts up on this flange first. Now we can line the other one up, make sure that looks good, and snug these bolts up as well. All right. Those are all tight. And if you have the other flange, tighten up that other flange right there.

Now, on the transfer case, you wanna clean up this sealing surface right here. Just use a scraper or a razor blade. Just be careful. Now, with that all cleaned up, you can take the gasket, and this only goes on one way. These bolts are not the same distance apart, so you might have to move it around a little bit to get it to line up. And I have a couple studs that are missing. That's okay. I'm gonna put those on once it's up there. Make sure the holes are all even. Now we're gonna put the transfer case back up. It's always good to use a helper to assist you when lifting this up, or try to use some kind of a jack to support it. All right. Let's go up. And we'll line this up. And that looks good. And now get those nuts on, and I'll put those studs in that came out. Now, do the best you can, if you can get a torque wrench in there and torque these nuts to 37 foot-pounds. It's obviously gonna be hard to get the top one. So, just tighten that the best you can.

And plug in all the O2 sensors, and if you have those safety locks, put the lock on, and try to mount it where it's supposed to go. Then we're gonna start hooking everything up on the transfer case. Start with this breather hose that goes to the top of the transmission. It just goes on to that elbow right there. Start connecting all the connectors. And the connector here for the four-wheel drive actuator, and then the speed sensor connectors. Just line those up with the speed sensors. And then there's another one right here, and there's the third one right there, and then this breathing tube is just gonna go right into here, onto that bracket. That's good. It's like an overflow. Secure this wire right here and any other areas where you need to secure the wires.

Now install the transmission mount and the two bolts, and snug those up. And then take this crossmember, and there's a little dip, and that goes on the driver's side. Slide these bolts in. Now, from the factory, these bolts on this side came from this direction, and you can reinstall them that way if you want, but it's somewhat hard to get past the exhaust. So, I just send them through this way, and it should not make a difference. And then put the nuts on the back side and tighten these down. Now I can lower the support for the transmission, lower the transmission jack, and take the two transmission mount nuts and put those on, and snug those up.

Now take the front driveshaft and slide it into the output of the transfer case. I made a mark on this yoke. So, just line that up with the mark on the U-joint. Put these retainers on, our U-joint cap holders, and tighten these down, and take a wrench and snug those down. And do the same for the rear driveshaft. Slide the yoke in first, and line the marks up on the yoke, on the back yoke, and put the cap over, and then tighten these down. And put these front shields up, if you had the other one as well. This vehicle only has this one. To fill the transfer case, it's always a good idea after you reinstall it to check the level, you're gonna take this nut off right here, that's the fill nut, and the level needs to be right at the base of that. So, check the appropriate fluid that you need to add, and just make sure it's at that level, and then use an 18-millimeter socket, or wrench, and put that nut back in place.

To add the transmission fluid or to top it off, you're gonna add it through the dipstick tube. Top off the fluid, and then you're gonna run the vehicle, and when the vehicle warms up, pull the dipstick out, and then check to make sure it's in the hash marks. Now, there is a hot hash marks and a cold, down below. So, while you're letting the vehicle run, at least make sure that it's in the cold area, and then you can adjust accordingly. Now, you wanna keep in mind the transmission cooler, which is located in the radiator. Sometimes there's an additional transmission cooler externally. Now, after you're having problems with your transmission, a lot of the times, the reason why is because those coolers are plugging up. Now, it's easiest to just replace the radiator, or if you have the ability to flush it, you could flush it, to prevent this happening again. And connect the negative battery terminal.

All right. The new transmission's shifting great. 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.


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