Pinion/Carrier bearings?

I think I have some bad bearings in my front axle. Grinding/growling noises that vary somewhat with speed, and a little vibe at 50+. The grinding seems to be getting worse. Does anybody have a rundown on how to replace the bearings/what else needs to be purchased along with new bearings? I am a poor college kid here--I do have decent basic hand tools. My understanding is that I will need an inch/pound torque wrench to check the bearing preload, although I'm not too sure on how that's done.

i can't see doing bearings on the carrier or pinion without a shop press. what a pain in the a$$. just buy an axle from a junk yard for 100 and swap it in. doing bearings is not nearly as easy as it sounds to do yourself.

what year XJ??? Try removing the front driveshaft and see if the noise goes away. Sure it isn't the wheel bearings making the noise??


Some late model XJs had carrier bearing issues. I had a friend who had junk ones in his mint 99XJ. We just replaced it with another axle from the junk yard, much cheaper than re-doing the gears.

mjma, you are so right. I had to replace the bearings on the front diff on my 1999 at 80k. Disappointing but what are you going to do.

Widgetjeep; I'd make sure that you accurately isolate that noise. They can be very tricky and can fool you. Have a drivetrain technician go for a ride for you if you are unsure; the test drive is generally no charge.

Replacing bearings is not recommended without the right experience/tools. Have somebody else do it for you or swap in salvage.

It's a 99, just like the two problem examples given in this thread. Hmmmm...I wonder about that year. A whole axle swap for a few bearings? Seems a bit excessive. Shouldn't it just be a matter of pulling the old ones off and tapping the new ones on? Is this something that needs to be done immediately, or can I put it off for a while until the next warm spell.

How lucky do you feel?

I toasted the front u-joint on the double cardon, of my rear drive shaft a few weeks ago on my '98. Drivehshaft U-joint replacement was easy enough, but the wicked driveshaft vibrations from the toasted u-joint messed up my rear pinion bearing somewhat.

It's not terribly bad right now, but the virbration/growl I'm feeling right now is one all too familiar to me. That's how I fried the rear end the first time through, by not acting on it quick enough. Had to get new gears that time through....

A master rebuild kit has been ordered, and should be installed next week by the shop. Not really all that bad, as it's going to cost me $475 for parts & labor..... I'm sure it would be a whole lot more if I "wait".......

You may want to first check the driveshafts themselves.... At first, they "seemed" solid enough, until I dropped them, and the u-joint damage was clearly more evident....

I'd look at the hubs first. Carrier bearings are often louder in reverse than forward. Pinion bearings can often be felt at the yoke, the seal often seeps when they are loose.
Jack it up and get the tire off the ground, grab it top and bottom and rock it a little. Bad hubs often sound like the sound is coming from the drivers side floor.

The pinion seal is leaking a little bit. I just replaced the axle ujoint on the driver's side (actually ended up putting a half shaft from an '01 wrangler in; bent yoke) and the unit bearings are good. This sound has been going on for at least 2-3 months. I think the hubs would have been toast by now. I don't use my 4wd very much at all (sadly). I have yet to take the diff cover off and inspect, mostly due to the fact that there's 10" of snow on the ground and I don't have a garage.

Carrier bearings aren't usually the type of thing that goes bad quick, I've driven on them for months. The test is to take the cover off and pry the carrier up, you can see the play.
I've never had any big problem changing them. Getting the cross pin bolt out or the rolled pin is about the trickiest part.
I cut the old bearing out with an angle grinder (I'm good with an angle grinder) keep track of the shims and take it to the shop and press the new bearings on. Most people recommend heating the bearing first. I've never had any problems with oversize or under sized replacement bearings causing pre load issues. Maybe I've just been lucky.
Have you looked at the transfer front bearing? Sounds in the drive train will fool you.
Put it in 4X and back up, if the noise is noticeably louder it's likely carrier or pinion bearings.

Haven't dropped the front ds yet, but I did put it in 4 and drive everywhichway for a while. Noise seems pretty steady. Hell of a loud engine and it's somewhat difficult to tell.

99, eh. Yeah, you may have been one of the lucky people to get some of the junk bearings.

Replacing the front axle is cheaper and easier than doing the bearings. You have to press them on, have them shimmed correctly, and make sure that the ring and pinion gears mesh correctly. I'd do the pinion bearings at the same time, which means you're setting up the whole gearset!! Most anyone can do an entire engine rebuild, tranny swaps, etc, but setting up gears is not something that I would recommend for just anyone. You need the proper tools and experience. If you mess up once, it costs big bucks. so it's best left to experienced professionals who can get it done right the first time!!

Anyways, we grabbed another HP30 with about 75k on it, complete disc to disc, and a new front DS (his double cardan was kinda funky) for 225, and they pulled it for us. It was great for me because I got to keep a bunch of spare parts off of it!!

On the ground in a driveway, with a helper who had very minimal experience working on vehicles, we got the swap done in less than a day. We did the ball joints at the time, because it was a good idea and we had to swap knuckles because his XJ had ABS and the axle we pulled did not. As I said, the guy had very minimal experience with working on vehicles, and essentially none with 4x4s, and he pretty much had figured out on his own that the noise must have been coming from the front pumpkin. He did manage to change both hubs himself, and after knowing that those were good, the pumpkin was the only other logical place to look.

Oh, one last thing, so just from talking to him he thought it was the carrier bearings. I told him remove the front DS, he did, and he said that it made a minimal improvement, but still the sound was there. If yours does the same.....

My local boneyard wants vehicle model year info---I want a HP D30 from what year range? I am still not completely understanding the whole issue with bearing replacement. Some guys say it's easy, but I can guess they got lucky with backlash and preload. I'll try the axle swap price and see what's less.

You'll want 92 to 99 or 00. I forget it they went to the LP in 00 or 01. Best bet is 95 or newer though. There are some slight differences in the brakes and hubs....I forget the years. You can swap brakes one way, but not the other. I'll let someone else clear that up. Worst case scenario, you could use the older axle, and swap on your outer knuckles, bearings, brakes, etc.

Also, while you're at it, it wouldn't hurt to do the ball joints. It's easier to do it with the axle out of the vehicle, rather than have to rip everything apart later down the line.

Wanna send me the spare shafts you get??

I just replaced the driver's half shaft with an '01 wrangler. We'll talk more when I get the axle and am ready--I may keep the extra shafts for emergencies. Send me a PM now so I remember! Do I need to get a new d30 with the same gearing as the rear?

How do I tell what gearing I have on the front? I've heard of this diff tag, but can't seem to find it--is it stamped in the cover? Also--if I get a swap d30 from a boneyard, does it need to be the same gearing? What I'm asking is--does the front gearing have to match the rear. It seems logical that it would, otherwise one set of wheels would be spinning faster than the other and that would lead to no end of problems.

Yes, the front and rear have to have the same gearing.

Sorry, don't know if there are any tags with useful info. Asking to have the diff cover removed to inspect the gears is reasonable and sometimes the ratio is stamped on the edge of the ring gear - there are pictures of that on the site here somewhere. Otherwise, while the cover is off count the teeth on ring and pinion and divide.

Widgetjeep said:

I think I have some bad bearings in my front axle. Grinding/growling noises that vary somewhat with speed, and a little vibe at 50+. The grinding seems to be getting worse. Does anybody have a rundown on how to replace the bearings/what else needs to be purchased along with new bearings? I am a poor college kid here--I do have decent basic hand tools. My understanding is that I will need an inch/pound torque wrench to check the bearing preload, although I'm not too sure on how that's done.

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I have a 99. When I first bought it I had a loud buzzing sound coming from the front.
It turned out to be the front driveshaft, had a lot of wear.
When you drive and it makes the noise, do you notice any change when you turn the steering wheel left or right? If yes, its the hubs.
IMHO I would not dump an otherwise good axle and install some junk that was laying in the rain for years. Replacing the carrier bearings is not very hard but not for a beginner. Bearing replacement will not change the backlash or tooth pattern. If the pinion bearing has been allowed to go to hell, it will affect tooth contact and possibly create gear noise after replacement.

The noise is always there, but it is louder on left turns at speed (i.e. more pressure on the right wheel). I did the 12/6 o clock shimmy test yesterday and there was no play in that wheel. Would the carrier bearing have more pressure on it on a turn as well or just the hubs affected?

Widgetjeep said:

The noise is always there, but it is louder on left turns at speed (i.e. more pressure on the right wheel). I did the 12/6 o clock shimmy test yesterday and there was no play in that wheel. Would the carrier bearing have more pressure on it on a turn as well or just the hubs affected?

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The carrier bearings are not affected because the axle shafts are floating through the carrier. My money is on a hub.
Hubs can make noise long before they go "bad".
I had a hub making noise for a long time before I replaced it in a 87 and a 96 XJ .
The right side seems to be the first to go.
I just replaced a hub on a Maxima using the sound as a guide. When compared to the other side as far as smoothness, couldn't tell the difference.

No s%*t?! I thought they went bad all in a hurry. Maybe I shouldn't take Jeep tips from my SVT Contour-driving buddy...I have to do the rear shocks today, so I'm gonna get a new hub and try that too. I'll post the results. Thanks!