How to Replace Differential Cover with Gasket 1994-2004 Chevy S10 Pickup

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Hi, I'm Mike Green. I'm one of the owners of 1A Auto. I want to help you save time and money repairing and maintaining your vehicle. I'm going to use my 20+ year's experience restoring and repairing cars and trucks like this to show you the correct way to install parts from 1AAuto.com. The right parts installed correctly that's going to save you time and money. Thank you and enjoy the video.

We're going to change the rear differential fluid in this S10. You might see the need to do this if you've been driving in rainy or wet conditions quite a bit. That's what happened up here in the Northeast. This March of 2010 we had about 5 consecutive days of rain and it looks like the differential on this truck got some water into it.

So tools you need are a wrench. You'll need probably a 3/8 drive to get the plug out, or a wrench to get the plug out and then this truck has 1/2 inch bolts holding the differential cover on, then a screwdriver, and then various tools to clean up the differential and the cover which would be a razor blade, sand paper maybe, and maybe some steel wool.

As I checked the rear differential fluid basically it's just a little plug that you use a 3/8 drive ratchet and take the plug out, and then I just stuck my finger down in there, and now what you can see is a bunch of foam. That indicates to me that a lot of water got into the rear end at some time and that's not really doing a good job lubricating the rear end so what we're going to do is we're going to just pull off the back cover and basically just change the rear differential fluid.

So to change the fluid you have to remove this differential cover. So the first step is to make sure you got the right gasket, and I'm going to answer the next question right now. Yes, use a gasket. Don't just try and use RTV sealant. Gasket costs nothing compared to if you use RTV and then you develop a leak, you lose all your fluid, and then you have to replace a differential. So I'm going to remove these 10 bolts. Then just use a screwdriver. You want to make sure you have a nice big wide pan to catch all the stuff. Then once you have it off, and you can see, actually I can see the problem. I would bet that this did leak some water down into itself. Here's the reason why you're going to need to put a new differential cover on. This is actually the top, and you can see how far down the rust has penetrated and I've tried to scrape this off somewhat, but this has just gotten so rough that it's a good possibility the gasket won't seal and I'm pretty sure on this rear end the reason the fluid in it was so foamy because water got into the differential and mixed with the fluid. Basically, that's the reason why you probably want to put a new differential cover on to get a good seal, and you also just want to make sure you scrape as well as you can around the differential and use a gasket and use good gasket sealant on it too.

So you can see I've cleaned off my differential pretty good. I used some sand paper and some steel wool. Don't worry about getting little particles of stuff. Obviously avoid getting as much stuff in here as possible. You want to avoid getting anything big in here, but if you get some little stuff in there you just use a rag and basically before you put new fluid before you close it back up, you're going to wipe it all down anyways. Try and pull as much of this bad stuff out as possible.

So you can see here. Here's my differential cover all cleaned up. I've put gasket sealant on it. Go ahead and put gasket sealant onto the differential itself. What you do is you put a bead on and basically you just follow the directions on the sealant. Oop. I don't want to get any in there. Just follow the directions on the sealant what it says to do is basically put it on, let it get tacky, and then put it together. So I put the bead on. I'm just going to take my finger and kind of smooth it out. I want to kind of avoid getting it up too close to the differential and what not, and the same thing on my cover, take my finger and just kind of smooth it out right around.

So now here's my differential cover and you'll notice I've put two bolts in. Those bolts don't have the bracket so they're kind of holding the gasket so that when I kind of slip this up in here I don't have to worry about the gasket walking away from me. Start that one a little bit. Get that one started. Then what I'm going to do is I'm going to put two bolts in down here and make sure that gasket's still kind of in the right spot. Now I'm going to put all my bolts in.

So I've got my torque wrench. I've got it set on 25 foot pounds, and I'm going to go in a criss-crossing pattern. Then after I've done that I'm just going to check them just go right around clockwise. Now we're going to fill up the rear end. I've already put one of these in. Generally these take, I think, about one and a half of these bottles, and I was wrong because it did take two and a half bottles. I can tell you for sure that the lubrication this is providing is a whole lot better than that foamy stuff that you saw at the beginning, and I'll keep putting it in there until I, oop, so there it comes out. So I'll just stick the plug back in, and we'll tighten that up and we're ready to go.

So we got the plug in and we're all set. One good thing to do is just take your rag and just wipe down real good all under here, all under here. Note whether or not up in here if your pinion seal is leaking. If your pinion seal's leaking, you'll see a bunch of fluid coming from there, and just note how dry it is down here because after you test drive it after you've put 50, 60, 100 miles on it just come down here and make sure you're not leaking. Also a good idea to get back under here after 100 miles or so and just tighten up the bolts again one more time just to make sure they're all tight. So that's how you do it.

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