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For those running a Detroit--Noise--grinding??

D

Deadman 94 xj

NAXJA Forum User
Location
Pittsburgh, PA
I have about 12 miles on a brand new set of gears (4.88) and a detroit locker. D30 open/8.8 locked.
The problem is, I'm getting a ticking at acceleration ONLY and it speeds up to a harmonic grind the more I accelerate. It does NOT do it when I let off the gas and as far as I can tell it does not do it in reverse. It's constant going STRAIT and when cornering, no difference.

I first thougt that it might be a t-case problem (chain) but I think it's coming from the rear locker. Other thoughts include a cv joint or something in the t-case.

Anybody have experience with this sort of thing? I plan to give the shop a call that did the install.

It's not real loud (like a bad pinion) but is loud enough to bother me.
 
my detroit in the 44 is silent as well...my cousins jeep had a grinding noise from his 8.25 in his 01 and it turned out to be a bad pinion bearing... it sounds like what you were describing. i would call the shop that did your gears and get them to look at it. if it was bad should have been replaced when they installed the gears.
 
Deadman 94 xj said:
I have about 12 miles on a brand new set of gears (4.88) and a detroit locker. D30 open/8.8 locked.
The problem is, I'm getting a ticking at acceleration ONLY and it speeds up to a harmonic grind the more I accelerate. It does NOT do it when I let off the gas and as far as I can tell it does not do it in reverse. It's constant going STRAIT and when cornering, no difference.

I first thougt that it might be a t-case problem (chain) but I think it's coming from the rear locker. Other thoughts include a cv joint or something in the t-case.

Anybody have experience with this sort of thing? I plan to give the shop a call that did the install.

It's not real loud (like a bad pinion) but is loud enough to bother me.
Click to expand...

Sounds like a bad ujoint in a drive shaft. If it doesn't make noise on Deceleration when there's no stress on the ujoint.
Could be a bad setup on the backlash and you are getting gear whine as well.
Pull the front Drive shaft for a test drive. Inspect the rear for a worn ujoint. Pretty quick tests to help isolate the cause.
 
The straps that hold the driveshaft to the pinion yoke should have been replaced as well when they did the swap. what brand gears? also, you can put the rear in the air and check the gear pattern if everything else comes up OK.

my gearset had some noise the first hundred miles, and went away after they got broken in, but no low speed noise. only noticed over 70/75
 
Thanks for the replies. I still can't get ahold of the shop...they must be off today.

There is no gear whine, just the ticking/clicking sound when I touch the gas. It almost seems like the sound it SHOULD make when cornering but only constant. Maybe the locker wasn't setup properly or there is a difference in my tire rotation for some reason. Tire pressure seems fine though.

The pinion bearing should be brand new because I gave him a complete Yukon overhaul kit. The gears are Yukon as well.

Also, I know what a bad u-joint in a stock/rear drive shaft sounds like but I'm not sure what kind of noise a cv shaft would make. THIS sound is a very *tight* clicking sound. The rear shaft is also brand new.

I'll pull the front and see what I get but I don't think it'll make a difference because it does it in 2hi.
 
The locker is only the carrier. In a straight line a Detroit is always silent. It is more likely that the R&P were not set up properly or the c-clips were not installed properly (c-clips half out sounds real likely with that noise description). I would not drive the vehicle and if you had the work done by a shop I would trailer or tow it back before you really damage something.

Deadman 94 xj said:
Thanks for the replies. I still can't get ahold of the shop...they must be off today.

There is no gear whine, just the ticking/clicking sound when I touch the gas. It almost seems like the sound it SHOULD make when cornering but only constant. Maybe the locker wasn't setup properly or there is a difference in my tire rotation for some reason. Tire pressure seems fine though.

The pinion bearing should be brand new because I gave him a complete Yukon overhaul kit. The gears are Yukon as well.

Also, I know what a bad u-joint in a stock/rear drive shaft sounds like but I'm not sure what kind of noise a cv shaft would make. THIS sound is a very *tight* clicking sound. The rear shaft is also brand new.

I'll pull the front and see what I get but I don't think it'll make a difference because it does it in 2hi.
Click to expand...
 
REVROK said:
The locker is only the carrier. In a straight line a Detroit is always silent. It is more likely that the R&P were not set up properly or the c-clips were not installed properly (c-clips half out sounds real likely with that noise description). I would not drive the vehicle and if you had the work done by a shop I would trailer or tow it back before you really damage something.
Click to expand...

Thanks, I'll look into that as well. The shop I took it to has a great reputation for this kind of stuff but I do remember him telling me that he had a problem getting the c-clips in. He said they were in but that it was a PITA. I'll find out more tommorrow and post back.
 
I was able to get the rear up in the air today and found that the noise is %100 coming from the rear dif.
I also did the locker "test" and everything seemed to work perfectly.

At first, under light throttle it would not make the noise but as soon as I applied more gas the noise came. I could hear and feel it on the diff cover.

I'm wondering if it's the ring gear rubing on the cover some how. That would make sence since it only does it when presure is applied to the driveline.

Any thoughts?
 
The 8.8 clips are always a PITA, but his statement makes me real nervous from some real painful experience. :shiver: Good Luck...

Deadman 94 xj said:
Thanks, I'll look into that as well. The shop I took it to has a great reputation for this kind of stuff but I do remember him telling me that he had a problem getting the c-clips in. He said they were in but that it was a PITA. I'll find out more tommorrow and post back.
Click to expand...
 
REVROK said:
The 8.8 clips are always a PITA, but his statement makes me real nervous from some real painful experience. :shiver: Good Luck...
Click to expand...

Well it seems like the shop is out for a while..jeep show or something.

I'm going to pull the diff cover and see what I can find. If the c-clips are loose, will I be able to tell if they're are loose without spinning/running the axle?

Also, would a bad bearing grind? What should I look for as far as the inner race bearings?

I want to fix what I can without having to remove the locker/gears so I'll check the gears and anything else I can see.

Any tips would be great. Thanks.
 
Update!!

I found my problem, it was the diff cover grinding on the ring gear..go figure.
There's a nice 2" gouge where it had been rubbing through.

I feel great about finding the problem but now I have a diff full of metal flakes/chunks that I NEED to flush out. I used a magnet and fished most of it out of the bottom. My question is, how should/could I get the rest of it out?

Any ideas.. I need help!
 
Nevermind, I posted too damn soon. I took it on a 50' run and it's still doing it. I removed the rear shaft from the t-case just to rule it out and it made no noise.
Next it's going back on the stands with the cover removed and I'll see what I can find. As of now it's either the diff or the rear shaft but I'm leaning towards the R/P.

I also found that it DOES do it in reverse as well. Like when going forward, it only does it under load.

The cover would have been too easy lol.
 
Update # 2

It ended up being the crush sleeve. Took it to the shop and they replaced it and all is well.

Thanks for the replies.
 
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