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Discussion Starter #1
On our recent 700 mile trip to the desert, I noticed that around 60 mph that when I let off the gas, I hear a whine/howl coming from under the jeep and at certain speeds, a faint grinding. Sounds like either the tcase or rear end. The gears are about a year old with less than 5000 miles on them and were set up by the most reputable shop around. Any ideas?

Nathan

Edit: It is an 8.8 rear end with a 231 tcase from an 88 xj
 

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not sure but let me know what you find out. pull the cover and check the wear on the gears and the oil.

i'm on my 2nd set of 4.56s. i burned up the first set by not breaking them in correctly. i know the 2nd set was done as best as possible but i'm still getting noise all to hell. not as bad as the first time, but still more than i should.

mine is going back to the shop next week when i get some time.
 

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Put the rear up on jackstands, put her in gear, and listen with a scope at the pinion and at the case to find out where the noise is orignating. My guess is pinion bearing.

Jay
 

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Discussion Starter #5
thanks jay, i will give that a try.
Nathan

Oh I forgot to mention, it only seems to happen when warm (i think) at highway speeds. I couldn't get it to do it today on the way home from work. I only got up to 60 for a minute though.
 

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I had/have the same symptoms you describe... except mine's more of a grinding than a howl on decell or going downhill at 60+. It started happening once I put on my longarms and jumped up to 6.5" from 4" I noticed the clearance between the wheel and caliper was very minimal due to the adjsuted pinion angle so I swapped on some different wheels and it the noise went away. I ground down the caliper a bit and threw my set that was causing problems back on. The noise was gone. Since then I put 33's on and the noise has come back. Whenever I grind off more caliper I paint where I grind so I can see if the wheel is still contacting it. There are spots where the paint is gone when I check every so often so I assume they are still grinding :lol: . So did you recently change you calipers, wheels, or pinion angle? Ask warfrat about this... he had a very similar problem if I can recall.

BTW When I took a trip up to the mountains with my dad and brother earlier this year I thought it was going to suck coming down the muntain, but it didn't make any noise at all... may have been the cool weather... hmmm
 

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Hey Nathan,

I have the same problem on decel and I just bought a '04 Grand Cherokee Limited and already put 2K miles on it. I took it to the dealer I bought it from and checked it out and they wrote and I quote "Noise is normal for this type of vehicle". I may take it to another dealer to get a second opinion.

Jody J.
 

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Nate,

What locker are you using? My Detroit slipped the bearings and made some pretty bad noises on decelleration. Be warned... they won't warrantee slipped bearings. They claim it's improper no matter who set up your diff.

John
 

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No locker right now :( just the factory ls.

I talked with the shop who set up the gears and he gave me some things to look over. I am still leaning towards the t case though. It only seems to do it when I have driven on the highway for some time. I am pulling the cover on the diff this weekend to see if the carrier bearings or pinion bearing is bad and has caused the backlash to change. The noise does not sound like a bad bearing but more like gear noise (ie the planetaries in the tcase). Anyone have a 231 for me? :D

Nathan
 

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NBaldwin said:
No locker right now :( just the factory ls.

I talked with the shop who set up the gears and he gave me some things to look over. I am still leaning towards the t case though. It only seems to do it when I have driven on the highway for some time. I am pulling the cover on the diff this weekend to see if the carrier bearings or pinion bearing is bad and has caused the backlash to change. The noise does not sound like a bad bearing but more like gear noise (ie the planetaries in the tcase). Anyone have a 231 for me? :D

Nathan
I have a 242 and a 249 you can HAVE for parts. I just bought another 231 for 20 bucks....throwing that bad boy in soon.

Sorry that 231 didn't last you as long as it should have :(
 

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JayH said:
What's that mean? "Slipped the bearings" ?

Jay
It means the "press on" bearings have become so loose on the carrier that you can remove them with your hands. Usually you have to use a bearing puller. When that happens, you will hear a slight noise at certain rpm's usually just inbetween accellerating and decellerating.

John
 
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