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rear end noise '98 XJ

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spiderman

Amish dude
Location
D.C. Area
I have the chrysler 8.25 axle, and it is grumbly in its tumbly! The noise starts at about 10 miles per hour, and I thought it was a wheel bearing, but after replacing both, I still have the same noise. It is louder under load, and goes away when I'm off the gas and coasting. Sound like a carrier/pinion bearing? If so, if I change those, can I use the same shims for the gears, or do I have to redo the whole setup? I assume you have to start over.

Thanks.
 
Z

Zombie

Random Dead Guy
Location
Sandy Utah
I'm lazy and cheap, so I start with the easiest and cheapest solutions first.
Have you replaced the Ujoints on the rear drive line yet?
 
S

spiderman

Amish dude
Location
D.C. Area
Nope, I will check the joints today. I was just thinking about the U-Joints.

I am using this jeep to tow my samurai up to moab in may. That's 2200 miles, and I don't want anything to go wrong with it on the way up.
 
jamesgeologist

jamesgeologist

Whiskey Tango Foxtrot
Location
Ogden, UT
If your 8.25" has an LSD then you may want to check if you have the right friction modifier for the LSD. Chryco makes their brand specific stuff available at the parts counter. If you changed the diff oil after changing the wheel bearings, then you likely forgot the friction modifier.

Jamesgeologist with a 98 XJ
 
waynehartwig

waynehartwig

www.jeeperman.com
Location
Mead, WA
Definately go with the u joints first... For one, if they haven't been done in a while, it can't hurt to have new ones.

You can change the carrier bearings without resetting everything. Just make sure the shims/etc you take off each side go back in the way you found them.

Diff oil might be a problem. Make sure you use somethign that is API GL5 or GL6 certified. Valvoline in the blue bottle is a very good choice... If you are towing, use 85-140, not 70-80w. If it's GL5 or 6 you don't need friction modifiers....
 
S

spiderman

Amish dude
Location
D.C. Area
Thanks for all the input. It does not have an LSD, and I used GL-5 80w90 oil with some lucas oil (1/4 quart) added to it. I will try the u-joint (it may have never been changed). All the u-joint problems I have had so far have reared their head with vibrations and not noises, so I didn't even consider that.

Thanks for the offer, DaveB, but I am stationed at Eglin AFB, FL. I may take you up on that in June, though. I will be up there for a couple of weeks then.

One more question: I don't want to pull the diff cover to find the gear ratio, and the cherokee had several close ratios available, so I don't want to guess with the old spinning the tire and counting the driveshaft revolutions trick. The front dana 30 has a tag on it, but the numbers don't obviously say what gears it has. By this, I mean that it doesn't say 3.73 or 3.55 anywhere on the tag. Anyone know how to decode it?
 
waynehartwig

waynehartwig

www.jeeperman.com
Location
Mead, WA
I can tell you what gears came from the factory... Post up the 7 digit code... Should be something like 610748-3. It will either be on the tag on the diff cover or on the front of the long side axle tube. It's stamped and hard to read sometimes....
 
waynehartwig

waynehartwig

www.jeeperman.com
Location
Mead, WA
spiderman said:
Okay, it's 610671-7

there was also a 55 before this number, and another number- 52069194AB.

THanks.
Click to expand...

There was probably a 3 in front of the 55, maybe it's not easily seen. You have 3.55's in a non disconnect, non cv, non ABS, open axle.
EDIT: oh, and that axle is a 97....So your XJ is probably a early 98 model?
 
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S

spiderman

Amish dude
Location
D.C. Area
I dunno... I was wondering about the 55, but for the life of me, I can't find the 3. I scraped red pencil over the tag to make the numbers legible.

Thanks agian for your help. I will change both u-joints on the rear driveline tomorrow and post the results. I'm crossing my fingers... I really don't want to dig any further.
 
Andy

Andy

aka. Hollywood
Location
Here and there....
Your not going to find a Dana BOM # on that axle. There should be a smaller tag on the diff cover with the ratio. If your getting a rumble under accel. it's going to be a carrier bearing, it's going to be best if you do all the bearings now. I have seen lots of 8 1/4 diffs with limited slips diffs lose the clutch pack clips and start digging in to the housing. If your not confident enough to do the job your self get to someone who can asap. And as for lube for the limited slip the Ford frictoin modifier is the best for all.
 
S

spiderman

Amish dude
Location
D.C. Area
1993yj said:
If you don't figure out the problem before the drive to Moab, I bet you will then.
Click to expand...

That's why I am worrying about it now. I know I can set the gears up with time and research, I have before, but it has been a LONG time since I've done it. I would much rather just find a low mileage used rear end and swap the whole thing in. Is the 8.25 more desireable than the 35? And if not, will the 35 bolt up fine? I'm really just concerning about the pinion mating to the driveshaft, I'm pretty sure everything else would be the same. Everyone keeps talking about limited slip, but it is not limited slip. Thanks for the help. I will check on everything tomorrow and see what I can find out about it.
 
88 Runner SAS

88 Runner SAS

Saving Money For Parts
Location
Monticello
Sounds like bearings in the rear to me too. I had a GM 10 bolt in my old pickup that the pinion nut backed off and it made the same noise you're describing. Never seen u-joints do that. Replaced the bearings and crush sleeve and it was good to go.
 
waynehartwig

waynehartwig

www.jeeperman.com
Location
Mead, WA
You can do bearings without having to reset the gears. Just make sure youp ut it back together the way it came apart - ie shims in the correct places. The only thing you have to worry about is setting the torque settings right....
 
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