Pinion bearing noise on '91 Cherokee Sport

I'm trying to discern the difference between a pinion bearing whine and a driveshaft bearing whine on the rear axle of my wife's '91 Cherokee.

The whine comes/goes with different throttle application, worse at 20-45 mph, almost disappears at 50+. Does not change with direction of travel. (Normally, I hear an axle bearing get louder/softer when turning, but go away or get worse when straight.) The sound is much like running extremely knobby tires on the street.

She says it has made this noise since she bought it used 3 years ago. The pinion seal area is slightly wet with lubricant, as is the left-side of the axle housing. Lubricant level is normal, and when checked looks fine - no burning or off-odor, which *probably* means that the ring and pinion are OK. Wiggling the pinion yoke yields no give at all - solid as a rock. All U-joints feel OK, however there is some slop at the transfer case output case shaft.

I plan to have it looked at in a few weeks, but I'd like to be armed with some information before the mechanic starts checking my credit score.

Is it possible that the slop in the transfer case rear output shaft could sound like a bad rear differential bearing?

What say you?

Reply to
JD Adams
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Cherokee's have this amazing whine about 20-30 mph. I can always tell when my wife is about to come home, I can hear her before I see her as she decelerates down our street at that speed.

Ours did that for the 10 years we owned it. Others do it too as I sometimes got 'faked out' wondering how come my wife was coming home so early only to see another Cherokee go by.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 'New' frame in the works for '08. Some Canadian Bush Trip and Build Photos:
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Reply to
Mike Romain

I figured as much. If my transfer-case/differential guy gives it a clean bill of health, it may become someone else's migraine.

Reply to
JD Adams

W had over 320K km on our 88 when we had to retire it due to terminal rust. We live in the rust belt big time. It was still running strong, just nothing to hold the wheels onto left, the floors were plywood...

If it hadn't rotted out, we still would have it, that's for sure, it ran great and was really nice about repairs.

Mike

Reply to
Mike Romain

We love this one. It still looks good, has about 110k miles and the drivetrain, wears new Michelin M/S's and is otherwise very healthy. It gets

20+ mpg and runs like a greyhound - it easily outruns most sports cars around here.

I'll see what my Tranny-guy says; if it can be muted a bit, it's definitely a keeper.

Reply to
JD Adams

Lucas is what is typically used to quite down motors, trannys, etc. I've never used it but it has been recommended to me many times.

Reply to
nrs

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