Truck Drive Train Noises Check the Drive Shaft Carrier Bearing

In this video, we're gonna go over some of the symptoms that you might find if you have a bad or defective rear driveshaft carrier bearing.

Hey, friends, it's Len here from 1A Auto. Today, we made our way underneath of a pickup truck because we wanted to talk to you about a rear driveshaft carrier bearing.

Okay. So if we're starting at the transfer case, which is pretty much in the center of the vehicle, as you make your way back, you're gonna see the shaft going right back to the rear differential. This long shaft is called the rear driveshaft. A lot of times these driveshafts will have two U-joints. Other times they'll have three or even more. If you have more than two, you're gonna need to have a carrier bearing. The carrier bearing would be located somewhere in the center of the driveshaft or at least close to center. And it would look something like this. This is a really poor example because it's in very poor condition. If you were to come along this side, you can see approximately where a lot of the rubber's actually coming right out of there and it's pulling out. This can be very dangerous. Some of the things that you might notice when you're driving in a vehicle that has a carrier bearing that looks like this, is vibration under acceleration, maybe you're going up a hill, you step on the gas, it's gonna put a lot of torque on this rear drivetrain, and it's gonna be able to shake around. You might also notice noise. Maybe you're hearing this just spinning around inside the area where it's at, or even a grinding noise if the bearings that are inside there are no good as well.

So just a quick explanation of what a carrier bearing actually does, if you have a vehicle such as a pickup truck with an extended wheelbase, or it's a very long pickup truck, you're gonna need to have one of these carrier bearings. The reason for the carrier bearing is because the driveshaft is gonna have to go from either the transmission or transfer case and it's gonna have to go a very long way to get to the rear differential. If you have a very long straight driveshaft, more than likely you're gonna have a balance issue. They kind of needed to make it so, there's a support in the center and then they'll have another joint, that way there with this being supported, there's less issues where you're gonna get flex or vibration from that drivetrain under acceleration or under torque. This right in the center here has to have a bearing, and it has to move freely.

Let's just talk about a couple quick causes of why something like this might happen. Well, if you have a bad U-joint, which this is considered a U-joint right here, and there's also another one down at the far end next to the pumpkin of the differential, and more than likely one up towards the transfer case in this case. If it's a bad U-joint and it's binding inside, maybe it doesn't have any more lubrication in there and it's heating up and it starts to bind, it can cause a lot of shake. And as this would shake around, it's gonna put premature wear on the rubber along here. You could also just have an issue where well, rubber breaks down over time. Maybe things get a little rusty and they start cutting into it. But basically the main reason why something like this might go bad over time is more than likely due to an underlying condition like I said, maybe a bad U-joint down the line. So you definitely don't wanna say, I only need a center carrier bearing without actually checking all of your U-joints first. Obviously our center carrier bearing is an extreme case situation here, having the rubber bushing pulling out like that is very extreme. It means it's pretty much completely torn away from the outer portion where it's supposed to be connected onto. Yours might not look like this, yours might be less apparent. You might only see little baby cracks kind of going in between where you think it's supposed to be connected, but there might be a real problem that you just can't see yet. To inspect that, you don't necessarily need to drop the whole rear driveshaft. You can go ahead right up here and you can take out the nuts, there is gonna be one there, one there, slowly bring this down, and then you can take this and kind of move it around. It's supposed to kind of wiggle around a little bit because it is only rubber. It's supposed to be rubber mounted. So it'll have a little bit of movement. Should it go like this? No. Should it go like this a little bit? Yeah, that's probably fine. Inspect it, check for cracks, any type of damage. If yours looks like this, you don't even really need to do that. The next thing I would do is pretty much just take down the whole rear driveshaft and I would inspect all the U-joints going down the line.

So we've got the driveshaft down on the ground because it's a little bit easier to diagnose and take a peek at these things. Without having anything connected to the vehicle, I can move anything around how I want. As you can tell, the bearings have noise. Would I have heard that up in the air? Probably not. If I was to grab onto to this, I could also try to move it around. It should not move around like this. This should be all connected inside there. And if I was to try to wiggle it, it should be able to do this a teeny bit, but to do this with just my bare hands, that's really bad. If this was to separate, what's to prevent your driveshaft from just going out of control while you're driving down the road?

Now, obviously we don't want to stop with just diagnosing the fact that this is no good. We need to see if there's any potential causes of why this could happen. Yeah, it could be dry rotted. It might be a little cracked and this separation could happen over time, it's quite possible, but there might be other issues. Maybe the driveline itself could have a binding issue in something such as maybe a U-joint of some sort. And it's also putting extra stress on the rubber bushing here. So what you would need to do while your driveshaft is out, just kind of grab onto here and move this around. Up and down feels nice and free. If I try to go side to side, I can almost feel like it wants to bind in one area. And then I go the other direction and then it's loose and then tight. And then this side right here, loose. So if you have a U-joint, which is this unit right here, that's binding in either direction up, down, left or right, or even just kind of trying to spin it around, that could potentially cause an issue that's gonna be detrimental to your carrier bearing.

If you're doing one U-joint, obviously you want to take a close look at all the rest. If they as though they're rusted or maybe the grease or anything might be missing from behind the caps, you'd want to replace those as well. The driveshaft's are already out. For this one right here, if you wanted to, you could carefully grab this, pull it out and you can take a peek on the inside. You see all those little roller bearings in there? They need to be well lubricated. If you pull this off and it looks like it's just dusty and red and full of rust, that means there's no grease in there and it's overheating and it's gonna potentially cause a major issue. Definitely replace your U-joints if that's the case.

Okay, friends, so we tried to make a quick video for you on certain things that you can look for to diagnose a rear carrier bearing issue. Hopefully you learned a little something along the way. If you did, and you want to talk about it, leave it in the comment section below. If you like the video, feel free to smash on that like button. It would mean the world to me. While you're at it, go ahead and subscribe and ring the bell that we're there you can be kept up with all of our latest content. Thanks.