bearings?

[volaredon]

I am on my 2nd XJ; my 1st was a "police package" '01 with heavyduty everything and my current one is a 97 "Country" not so "heavyduty" but more "luxury" (compass tweed cloth seats, cruise cont, etc)
During the 5 years I had the 01 I had to replace the rear end (Dana 35) because someone had previously replaced the carrier bearings and it appears nicked up the "journals" that the bearing inner race seats on, and then "turned them down" in a lathe (there was a "witness mark")to clean them up; so it was less than a "slip fit"; it was faster and cheaper to go to the JY and get a rear end (thanks to picn n pull) than to fix the old one; this was like the 3rd day I owned it; mileage was around 94K;
At 160-some K the pinion bearings went bad--started howling; coincidentally right after I replaced all the front bushings with urethane; so I went and bought all new bearings races and seals and rebuilt that front diff. (but boy did the urethane improve how the Jeep rode and handled)
my son rolled/totalled this one at 169K.
so I bought the 97 to replace it w/101K miles; At about 110K the pinion bearings went bad; another trip to Pic n pull) this one has the 8-1/4 rear.
Now 6 months later at 114K the front pinion bearings are howling like the ones did in my old 01; and within a week of that starting (I have not had a chance to do anything about that problem yet) my bearing in my AC compressor nearly locked up; it took me some running around and a few calls; but I did find "just" the bearing; most wanted to sell me a whole new compressor and clutch at ~10X the cost; why when the compressor works just fine?
so on my 01 there was about 65K between problems with the front and rear diffs, on my 97 there was about 4K (and at much lower mileage) plus the AC bearing; I have had Wranglers (still have a TJ) and never a differential problem!
I have never put a lift kit in; these Cherokees are my wife's daily driver; 4WD is only used as needed for winter driving; they have never been mudded (at least during my ownership)
is this typical? why am I having so much bearing trouble? I have only ever owned Dodges and Jeeps; never a front wheel drive anything; on my Dodges I very occasionally have a bearing problem; my Wranglers never; (I'm on my 2nd one of those too; and have my 2 brothers' Wranglers to work on whenever they have an issue as well)
I didnt think anything of this 97 Cherokee when the rear end pinion bearings started squealing; but now the front axle this soon afterwards?
and teh AC clutch bearing at the same time as the front diff? Is there a common denominator here that might be causing all these beraings to fail;? I've seen these vehicles at over 200K without issue that have never had differential bearing issues. WTF?
I guess I go see what carQuest wants for the Re Bearing kit tomorrow.

 

[superj]

my 95 had the compressor bearing go out also. other hten that, i have never had any trouble with 3 or 4 cherokees we have owned. no trouble with the one wrangler either though.

 

[MudderChuck]

I've never had a pinion bearing go on any of my XJ's, D35. But have replace carrier bearings on most, between 130 and 150 thousand miles. I typically run mine at high speeds for long distances and always figured this may be the cause (heat). Or maybe it is just fair wear and tear.
I do know my Dodges with the collapsible pinion spacer sleeve weren't fond of excessive drive shaft angles. The collapsible spacer (sleeve) would crush (mostly from overloading), though the bearings seemed fine and I reused them, just replacing the collapsible sleeve.
I've had my drive shafts go out of balance for various reasons (usually U-joints) and had that eat up the seal eventually, though again the pinion bearings seemed fine.

 

[volaredon]

2 Cherokees and both with differential bearing issues on both ends of the vehicle; at what I think is "too low" of mileage to have those issues; neither of my Cherokees have been modified from stock, or run "offroad";
I have had other vehicles with Dana 30s, Dana 35s, (01 had that out back as well as both my Wranglers too) and too many to remember with mopar Corporate 8-1/4 rear ends;(the current 97 Cherokee has this in back) and damn little differential trouble; but for BOTH my Cherokees to have this same problem and at both ends of them, it definitely seems weird; I remember something from back in the late 80s early 90s when I worked in a Dodge dealership about an incomplete ground somewhere, a common problem on teh Dodge Omni and Ply. Horizon (remember those cars?) and somehow the ground was completing its path via the hubs and front wheel bearings and they had a "run" on bad ones because of this til the "engineers" figured out the root cause;
Being I'm "batting 1000" with differential problems on Cherokees (I love them otherwise) I was wondering if there was something along this line I should be looking for; I see many retired in teh junkyards showing 200K+ on them though I hav no way of knowing the history of repairs on any of them; whether these retired ones may have had that repaired somewhere along the line.

 

[MudderChuck]

The only thing I can think of as a cause, is possibly somebody changed out the seals and reassembled using an impact wrench on the pinion nut. I've heard of many dealer mechanics say that is the way to do it, I remain skeptical. I'm kind of anal about bearing pre loads and when not using new gears, try my darnedest to get the bearings back in there as near as possible to the original position and pre load and then double check the pre load with an inch pound torque wrench. I've found a few thousands loose, to never cause any real trouble, while even a little too tight, can cause swelling from heat, spall the bearings and self destruct pretty quick.
My test for pinion bearings is, no noticeable lateral movement (I usually slap the side with my palm), if the yoke moves in and out, they are usually beyond salvage (or on some models, the collapsible spacer has collapsed to far).
I've replaced a lot of bearings in pumps and other machinery, I've got a pretty good feel for, correct, not too tight and not too loose (old school).:shades:
I've also heard to never use the original pinion nut over again, I always do anyway (with a dab of Loc Tite) and have never had any issues.

 

[volaredon]

Yeah I can see where your criteria for "bad" would be; but in my cases both front and rear, what I have found is that upon disassembly, I remove the carrier and spin the yoke by hand before pullig the yoke nut and I can feel the "roughness" in the bearings as I spin them by hand; and so far it has always been the bearing at the yoke not at the gear end of the pinion;
on that 01 I redid that front diff like 6 weeks before my son totalled that vehicle and in that time it was quiet and worked well; I had a dealer mechanic buddy gve me a hand with it and he assembled the crush sleeve and yoke nut portion of it; and being that we were on (short) jackstands and no room for a torque wrench or pipe wrench to "do it right" he gave me the "ah I do this all the time" answer; I was critical of it but it seemed to do OK but again I only owned that Jeep for another 6 weeks after we rebuilt taht front diff; maybe not long enough for the way it was done to show up as a problem;
I bought the 01 with 94K on it and the 97 that I have to replace the bearings in now had 101K on it when I got it; the front diff rebuild on the 01 (the rebuild that I know of, that happened while I owned it) was at like 165-167K (had 169K on it when totalled) and the 97 that I now have to rebuild only has 114K on it;
so that means that if they were both done at a dealer prior to my ownership, and my rebuild would be "rebuild #2" on the unit then they must be using some really crappy materials to build them in the 1st place;
so if my 01 was redone prior to my ownership that started at 94K and the 97 at 101 K, then WOW;
I didnt feel bad about rebuilding teh 01 at 160-someK miles; but this one at only 114K? even if it is the 1st RE build, that seems too soon from new; if this is rebuild #2, that is really shocking.

On the 01 I know the carrier bearings had been done before I got it; I went to redo it the 2nd day I had it since I bought that one with a howling rear, and that's when I saw what I noted in a prior post; it was quicker and cheaper to put a JY unit in than to buy a carrier (especially since that one was originally a TrakLok)

what gets me though? these are both Dana 30 front ends; I have a Dana 30 in my 97 TJ; and had a Dana 30 in my 93YJ; and never had issue with either of those; is there a difference between a XJ Dana 30 and a TJ/YJ Dana 30?
I have issues with the differentials at both ends of both XJs; but never with either Wrangler; now that I do not understand; the only thing I can think of here that I have any "control" over to cause this is that the XJs have been primarily bought for my wife and she puts the majority of the miles onto and I have primarily driven the Wranglers;
but what don't make sense there? is that I definitely drive "harder" than she does..... yet her vehicles are having the problems.
but when our son totalled the 1st XJ? I asked her point blank what she wanted for her next vehicle; and made a few suggestions; (most of which were vehicles that make me cringe; the only vehicle that I suggested at the time that didn't do so, would have been a full sized rear drive V8 powered Dodge van, like I used to have) and her answer was "I want my Jeep" and "if I can't have "that" Jeep (the buyback from the insurance was way too high for my liking at $1100 so I let them have it) I want another one"! so I got her another one; 4 years older but with (at the time) 70K less miles than the totalled one. and that would be the one that I am having bearing trouble with now, 10 months later. dang near exactly a year since rebuilding the front end in our now-totalled one....

 

[volaredon]

UPDATE; I rebuilt the front diff yesterday; I started it Thurs but didn't realize til I got it all apart, that Car Quest had sold me the wrong bearing kit; they sold me a "low pinion" kit and I have a high pinion; I didn't think of it at the time since it was the same exact kit I got, also from them, when I did my '01 XJ, for which it was correct; this was my 1st high pinion Dana 30 I'd ever done; til I found out the outer pinion bearing was wrong, (from the kit) and the crush collar would not fit the pinion, I had thought that someone had rebuilt the differential once before (and wrongly) when I saw mine came apart sans crush collar! so I started looking online at places like Nat'l Drivetrain and Randy's R&P, and saw the difference; the shim setup is easier I think than the crush collar style especially when you gotta try and tighten the yoke nut to tighten the crush collar on your back a foot off the ground;
all the outer races were pitted and "spalled"; the carrier bearings were definitely wasted.
I had done this at a buddy's house since my garage is so packed. so it was "down" in his garage for a couple days.... and on the way home it had a louder different-pitched noise than it did before; I wound up having to replace the driver side hub bearing too. I did have to "beat on" them a bit to get them off. (it did feel "rough" when I spun it while I had it off, in my hand) so screw it; it didn't make sense to rebuild the whole diff except for 1 bearing so I replaced both hub bearings....
so hopefully I'm done with this thing for a while;