This Is What Happens If You NEVER CHANGE YOUR DIFFERENTIAL OIL!!

What do you get when you cross your rear two wheels with your driveshaft? Your differential. And this is what happens when you don't change that oil. Many of you like me drive older vehicles with say a hundred thousand miles or more on the clock. And many of you like me have never gone out into the garage and said, I know what I'm going to do today. I'm going to change my rear differential oil. Yeah, it just doesn't happen like never. Well, never say never because every given day is an opportunity to turn it all around or at the very least to change your diff fluid. And that is precisely what I'm going to do today. Like right now, I'm going to change the diff fluid. I'm working on my 1995 GMC Suburban. This thing's got the 10 bolt, 8.5 inch GM locker in it. And I'm pretty sure that the fluid has never been changed. This is stock from the factory. This vehicle only has about 78,000 miles on it. So I'm not expecting anything crazy, like parts to be falling out when I remove that rear diff cover, but you never know. All right. So the first thing on the list is to go ahead and jack up this vehicle and put it up on jack stands. And I'm going to put these jack stands on the actual frame of the truck. The goal here is to drop that rear end down as low as it'll go. Now that I have it nicely supported with two six ton jack stands, I also grabbed a set of three ton jack stands for backup. Next I'm using my half inch ratchet with an adapter down to three eighths and an extension. I'm going to use this to go ahead and loosen this fill plug hole before I take off the rear diff cover. This way we know that that thing is not locked in there and we can actually refill it after we remove the old fluid. Now, before we jacked up this vehicle, that rear differential was tucked way up in there. That rear gas tank is roughly 43 gallons and it is definitely in the way. So jacking that vehicle up, putting it up on jack stands and letting that rear diff hang as low as it can is a great way to gain some extra room. I'm going to go ahead and take my three eighths inch ratchet and a 13 millimeter socket and just start removing the bolts. I've chosen to remove all of the bolts except for the very top center bolt. I've also chosen to take a piece of cardboard and basically map out where these bolts go so that I can be sure to put the same bolt back in the same hole. Now we get to the fun part. All of the bolts are removed except for that top center bolt, which is loose. And we're going to go ahead and take our old crusty Harbor Freight screwdriver. And oh man, look at this old nasty diff fluid. Boy, am I glad that I'm getting this stuff swapped out. This stuff looks burnt to a crisp. Look at how dark that is. Yuck. I would not want to rely too much longer on this old fluid. Keep in mind guys, this vehicle only has 78,000 miles. Yes, it is very, very old, but 78,000 miles. This fluid is pretty dark. Make sure you have a drain bucket to catch this nasty fluid and even some plastic under that just in case. And here is the top bolt. You can see we left in so that this rear diff cover would not fall as we crack this sucker open. Now that all that fluid is drained out, I'm going to go ahead and remove that top bolt. I'm going to apply pressure to the cover so that it doesn't fall. And by hand, just remove the bolt. Then we'll pull that cover off and reveal the differential. Wow. And it is pretty black from this fluid. Here you can see the rear diff cover and especially that magnet. Boy, are those magnets needed here more than ever before. Look at all of the metal shavings on this magnet. It's incredible how much metal shavings build up on this thing. This is a testament as to why you need to swap your rear differential oil per the manufacturer's recommendations. I believe on this GM truck and most of the GM trucks that carry the same rear end, it is recommended at the first 30,000 miles, and that is because when you first start driving your brand new vehicle, these gears need a chance to break in and during that break in process. Well, yeah, there's a lot of metal that comes off these things. So swapping out your rear diff fluid at about 30,000 miles is extremely important. This one, unfortunately has never been swapped, but Hey, I think everything looks pretty normal here, so I'm in the clear further evidence for having never been changed. This is the original GM differential gasket. All in all, not bad for being 24 years old. We need to clean this thing out. So the first thing I'm going to do is throw on some rubber gloves and start wiping it down with an old rag. Man, look at the metal shavings that came off that magnet. I'm just going to do my best here and get as much metal off of this magnet as I can. You can see with just a couple of swipes of an old rag, the inside of this diff cover is actually coming pretty clean. Now I'm going to take this putty knife and very carefully begin the process of removing this old gasket. And wow, it seems to actually be coming off very easily. You want to make sure that you're not scraping or scratching into the diff cover because you don't want to leave any marks or scarring, anything like that could lead to leaks in the future. Here, the old gasket has been completely removed, but as you can see, we still have a lot of work to do on the gasket surface. And if we take our original GM gasket and lay it on top of our brand new Fel-Pro gasket, you can see that the holes line up perfectly. I'll put a link down in the description below this video for this exact gasket. The first part of the process in preparing this diff cover gasket surface is to take a razor blade and try to scrape off any remaining gasket material. Now that you have that as clean as possible with the razor blade, I'm going to take this 3M very fine sanding pad and basically buff down this surface to nice shiny metal. Now to go over the top and to get it extremely clean, I'm going to take this brake parts cleaner and spray out the whole inside of this diff cover, as well as the gasket mating surface. You most likely do not need to do this, but hey, if you have the brake parts cleaner, why not? Now I mentioned how dirty the inside of this differential was, and you saw it. It's completely black, burnt and caked on old diff fluid. So I'm even going to take this brake cleaner and spray that out. Next, we need to replace this diff cover. The easiest way I've found is by using the top center bolt to not only keep that gasket in place, but also just to start that sucker and get this thing hanging. Now for me, I'm going to go ahead and throw on some blue thread locker on each one of these bolts. This will give me just a little peace of mind that these bolts aren't going to come loose in any way. Definitely make sure you hand start and hand tighten each one of these bolts before cranking on them with a ratchet. After hand tightening, I'm going around with my torque wrench and torquing each one of the bolts to 10 foot pounds. This is just the first pass. After that, I'm going to go around them again and now tighten them to 30 foot pounds. Now that the diff cover's on, we can work on refilling this differential. Now you may not have to do this, but I'm using my vacuum here right alongside this plug as I remove it. Just for a little extra insurance that none of this crud is going to fall down inside that hole when I take this plug out. Now, as for the lube, the manufacturer calls for GL580W90, but I found this awesome Lucas fully synthetic 75W90 and it is GL5 rated and I'm going to go ahead and use this. You can see what I've come up with here to make the job of refilling this thing a little easier. By using a little bit of this clear hose, I can raise the bottle up even higher and squeeze it with both hands and make sure that nothing spills. Man, after that first bottle, my arms were tired. So here is another added benefit of using this hose. I went ahead and jammed the bottle up in between this exhaust hanger and the frame. Then I made a cut in the top of the bottle to allow air in. Now I'm just going to go ahead and let gravity do the work for me. As for capacity, this differential uses roughly just under two and a half quarts. You'll know it's full when it actually starts leaking back out. The bottom of this fill hole is actually the fill line too. So as you can see, once it starts dripping back out, you'll know it's completely full. Now take your plug and replace it. All right, guys, we did it. We did it together. This was my first time ever changing out differential fluid. Hopefully I won't have to worry about this for a long time to come. Just make sure you keep an eye for any leaks or anything like that. You may need to snug those bolts down if you do see some leaks. Also, it is possible that your differential needs an additive. So definitely check with your manufacturer for that. All right, guys, I really hope this video helped you out. If it did, make sure you leave a comment below. Hit the thumbs up and also subscribe if you're not already. You can find me on Instagram at OneRoadGarage and my website, OneRoadGarage.com. Thanks again, guys, for watching. I know your time is valuable. My name is Jimmy. This is OneRoad, and I will see you in the next one.