I know I have a bad pinion bearing. Just serviced the dif, no metal shavings. How urgent is this to get fixed? Obviously I want to asap, but its going to run 6-800 bucks. Do I need to park it? Ok to take short distances? I also need to replace front axle u joints and hub bearings, but I am going to let the shop break those bolts first doing the pinion.

 

if the pinion has detectable lateral freeplay, (ie you can shake it up & down) I wouldnt drive it

If it doesnt make noise all the time, I would probably drive short distances

 

$6-800? I'd load up some 1/2" drive tools and take myself to that Nashville Pull-A-Part and pull an axle before I dropped 3-4x the cost of a JY axle on a pinion bearing.

 

Thanks for the responses. I probably should have clarified that it’s the front axle. Rear is fine.

 

Wouldn’t a new bearing have a longer life than picking one with 100k plus miles on it. I am not after cheap, I want my xj to last another 20 years.

 

I guess it depends on the quality of work being done by either party.

Are they going to reuse your old ring and pinion?

 

try another place, let him look at it and see what he thinks. Gears might be acceptable and maybe not. You will never know until it is apart . Go to a shop that does rearends, not just some mechanic shop. I got burned for just a pinion bearing and started howling after 6 months. No short cut,s on this kinda stuff

 

I've never done a pinion bearing, but reading a very thorough walk-through of the process for replacing it (in the D30, front axle of a Jeep), it is NOT a job for the faint of heart or less-than-precision mechanic. There are a lot of really exact measurements and chances to be repeating a lot of work several times over for the sake of a thousandth of an inch.

As mentioned, this is NOT the sort of thing to take to any random shop. I would want a shop that specializes in Jeeps/Axles and has done a few of these before with lasting success. This really is the sort of thing that you should consider replacing the whole axle if you can find a good one. I'd trust myself on that one a hell of a lot sooner than the pinion replacement I think. This is doubly true if there is ANY question of the shock mounts or control arm brackets on the axle....

If it were me and I was SURE I had a bad pinion, I'd start with the junkyard search (and only because I have a manual which has a different gear ratio than most XJ's of similar years) and only after being sure I couldn't find a matching axle in decent shape, then call the Jeep shop with a good reputation not too far from me.

 

Assuming this is front diff, you can drive in rear wheel drive but you will want to stop the front diff from turning. if you have manual hubs, unlock them, if autohubs, then you really cant stop the front from turning, except to park it. ( unless you maybe can remove the guts from the autolocking hubs, thus making them free spinning, I dont know that)
as for damage if you keep driving, it is a risk, it all depends on how bad is bad, and how you drive. You certainly can cause more damage if the bearing is bad and you keep driving, the whole diff could be destroyed, the ring and pinion could be wrecked, or maybe nothing bad will happen for a while. feel like gambling?

without seeing the looseness of the pinion bearing I cant recommend you keep driving.

what signs of bad bearing to you see? a wobbly input shaft is probably a very bad thing for the gears.

A wrecking yard axle can probably be had for little money, and installed for now if you must drive it and lack funds to rebuild your current axle.

otherwise research your auto locking hubs, if so equiped maybe they can be forced to remain unlocked by opening them up and removing a part?

good luck

 

Well, you certainly don't want to use 4wd with a bad front pinion bearing.

But, you can just remove the front driveshaft and drive it in 2Hi until
you come up with a solution. The pinion will have no load at all on it
and the bearing won't get any worse, unless there is already a roller
broken in it. Plus, you would save your driveshaft u-joints from extra
wear from being attached to a wobbly pinion.

 

thanks for all the input. The shop that gave me the estimate is a 4x4 specialist. They do this stuff all the time. I have don’t quite a few things myself, but this is something I don’t want to risk without experience or tools.

Just going to park it til I can get it in the shop. Don’t want to risk it.

 

Think you'd be fine driving it to the shop. I recently bought my xj, and never noticed just how horribly loose my front pinion was, got quoted 450 to do the work, ended up doing it all myself. Made a thread on here not too long ago. It's doable for sure, but I also bought a ton of tools to help do the job properly. Oh my original point was, I drove it home like 50 minutes with that pinion like that and it didn't seem to hurt it. I'd imagine the dude who owned it drove it around like that as well. These things are tougher than you think.

 

That previous owner was me. have driven my xj for 20 years. The howling from the front has just been getting worse this last month. Has also been officially diagnosed from the above mentioned shop. I have done a dif service since, and there were zero shavings and gears looked ok. Hopefully I can get it done this week.

 

Finally scheduled to get the bearing done. The shop is a month out. In the meantime trying to figure out how to get place to place without damaging gears. I thought about dropping the front drive shaft til then. Would this help at all? Does the front drive shaft turn even when 4wd is disengaged?

 

It wouldn't hurt but it's not adding much in the way of extra damage if you are not in 4wd. It spins no matter what but if there's no load on it it's not really doing anything. If the drive shaft is bad I would take it off for now.