Rear Differential Bearings?

KatABro · Apr 6, 2006

Hello all --

I own a 1996 Cherokee (XJ) that I bought used with some basic mods -- 4" lift, 15" wheels, mud tires, etc....

I took it into the shop last week for a once-over, and was told that I needed to have the rear differential bearings repacked. Also, that failure to do so could cause a "Critical Failure" in that the entire rear axle would need to be replaced if the work wasn't done soon, due to wear on the axle. The mechanic took me on a ride-along to demonstrate, and pointed out what he called a "roaring sound" coming from the rear end. I don't know if I'd call it so much a roaring -- in fact, I had thought it was just noisy nubby tires on pavement.

He quoted me a price of $650. He said that if the axle ended up needing replacing, it would be at least another $400.

I know my way (basically) around an engine, but know very little about the undercarriage. Especially due to the mods. Does this sound legitimate? If so, is the price anywhere near the mark? I'm living in a new city, and don't have a reliable mechanic yet.

Thanks,
KatABro

Kejtar · Apr 6, 2006

KatABro said:
Hello all --

I own a 1996 Cherokee (XJ) that I bought used with some basic mods -- 4" lift, 15" wheels, mud tires, etc....

I took it into the shop last week for a once-over, and was told that I needed to have the rear differential bearings repacked. Also, that failure to do so could cause a "Critical Failure" in that the entire rear axle would need to be replaced if the work wasn't done soon, due to wear on the axle. The mechanic took me on a ride-along to demonstrate, and pointed out what he called a "roaring sound" coming from the rear end. I don't know if I'd call it so much a roaring -- in fact, I had thought it was just noisy nubby tires on pavement.

He quoted me a price of $650. He said that if the axle ended up needing replacing, it would be at least another $400.

I know my way (basically) around an engine, but know very little about the undercarriage. Especially due to the mods. Does this sound legitimate? If so, is the price anywhere near the mark? I'm living in a new city, and don't have a reliable mechanic yet.

Thanks,
KatABro

Diff bearings repacked? Ussually when they go bad you just pull them and replace them! Replacing an axle?? Why??? Due to bad bearings? OK.... follow these steps:

1. Never visit that mechanic again
2. Talk to people who are local (or semi local... JNJ maybe?) and see if they can recommend a fellow jeeper or a shop to check out the rear end for you and do the work if needed.

Last time I checked for $650 you should be getting new gears, and bearings installed and still have money left over.

cal · Apr 6, 2006

Not to mention that the rear diff bearings live in oil, and don't get packed to begin with..

The mechanic was feeding you a line.

ChiXJeff · Apr 6, 2006

Gawd, I'm gonna agree with KetchupJar.

Repack rear diff bearings? With freakin' what? The diff bearings are lubed by the diff gear oil. There's practically no way that an axle shaft would need to be replaced if a diff bearing failed, the splines just float in the side gears inside the case.

This is not to say that you don't have issues, though. Some other questions..... what size tires (and make?) Gears (original, or replaced with what?) Auto or stick?

Normally, a full gear set ran an average of $300. May be less, may be more, depends on where you are, who'd doing it, etc. Replacing just the diff bearing would just be resetting the preload, you wouldn't have to mess with the pinion depth, and may save a couple of bucks. Parts extra, but bearings and shims should only be a few dollars.

In short, you do need to find another mechanic. This one smells a fat wallet.

Rick Anderson · Apr 6, 2006

Guys I'm a Noob to 4X4 and truck like suspensions, so correct me if I'm wrong;

Improper lift can create all sorts of problems with driveshafts and axles. I'd suspect pinion bearings and seals going bad before the differential bearings, but I supposse its possible.

Agree with the re-packing comments, many bearings need to be repacked with GREASE, but not those in the axle, thats why there is axle fluid you have to change, its what lubricates the bearings.

What About Axles Shaft Bearings?? Are those lubed by the axle fluid as well?? Could his mechanic been talking about the axle/driveshaft bearings needing repacked?? I'm I wrong, aren't the bearings on the axle/driveshafts out on the end of the axle also lubed by the axle fluid running down the tubes?

Definitely get a 2nd or 3rd opinion, the guy doesn't sound legit.

Kejtar · Apr 6, 2006

Rick Anderson said:
What About Axles Shaft Bearings?? Are those lubed by the axle fluid as well?? Could his mechanic been talking about the axle/driveshaft bearings needing repacked?? I'm I wrong, aren't the bearings on the axle/driveshafts out on the end of the axle also lubed by the axle fluid running down the tubes?

Definitely get a 2nd or 3rd opinion, the guy doesn't sound legit.

The axleshaft bearings for rear axles also are submerged in fluid.

KatABro · Apr 7, 2006

Thanks, guys.

I was skeptical. Glad I didn't give him the go-ahead without checking up on it first. I'm disappointed, because this is "the" Jeep shop in Austin. I'll be looking for a 4WD shop next, I guess.

Although I'd love to go back and rediscuss the job he recommended -- and suggest that he "repack" the bearings in pickle juice. Think that'd get the point across that I'm onto him?

I'm glad I joined the forum. I'm sure I'll have many more questions -- this is only my second Jeep, and the first with any mods. My first Jeep was a pristine stock 91. Well, pristine other than the fabulous ABS system it had. Meh.

Thanks again,
KatABro

Digger87xj · Apr 7, 2006

you sure he said repacked? or did he say replaced and you misheard? 650 is about right as book time is 6.0 hours, and then probably 160 in parts. At my shop @ 80.00 an hour thats $640...

I don't think he was feeding you anything. Also, he is very correct about total failure if left for very long. Bad bearings will ruin a ring and pinion very very fast.

If you can get bearings, R&P and install for less than 650 I'd be very scared at quality of work and the parts.

Just my $.02 from a 20 year mechanic....

Kejtar · Apr 7, 2006

Digger87xj said:
you sure he said repacked? or did he say replaced and you misheard? 650 is about right as book time is 6.0 hours, and then probably 160 in parts. At my shop @ 80.00 an hour thats $640...

I don't think he was feeding you anything. Also, he is very correct about total failure if left for very long. Bad bearings will ruin a ring and pinion very very fast.

If you can get bearings, R&P and install for less than 650 I'd be very scared at quality of work and the parts.

Just my $.02 from a 20 year mechanic....

1974-2002 Jeep CJ, YJ, TJ, XJ (excluded 8.25 Chrysler)
Yukon Gear Master Overhaul kits (with Timken bearings) Ratio 3.54, 3.73, 4.10, 4.56, 4.88. Other ratios available per application.
Price $442.24*

Labor? If you're paying over $200 then you're paying too much. And that's a general estimate without looking for a deal on the R&P. So..... you were saying?

cal · Apr 7, 2006

I had my 8.25 rebuild just before I sold it. I paid $91 for a master install kit using timkin bearings, and $150 labor. I didnt have to buy a new r&p, but this guy didnt say he needed one either.

I didnt pay 650 to have -both- of my axles geared, parts and labor.

-C

90cherk · Apr 7, 2006

My axle bearings needed replacing after about 150K original miles and since one bearing had gone bad the axle on that side need replacing (it had a nice groove ) plus there was a "hum" which sounded like excessive tire noise.

At that time they gave me a newer pulled axle from another rebuild they had been working on and replace the bearing all within a two hours max. I stood there with the mechanic the whole time watching and learning. Cost a couple hundred but this was a few years ago.

I suggest taking it to a 4x4 shop that does a lot of suspension and rearend work, not a general shop. I imagine ther are quite a few to choose from in your area.

Rear Differential Bearings?

KatABro

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Kejtar

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cal

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ChiXJeff

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Rick Anderson

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Kejtar

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KatABro

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Digger87xj

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Kejtar

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cal

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