Weird Differential Noise. Any Suggestions *video*

[Luvs2slide]

I installed another diff into my car and now i'm having some weird grinding noise. Havnt got a chance to get a good look yet, but here's what I know:

1. Changed diff case from a s13 style (no bushing) to s14 (bushing)
2. Changed out rear back plate to bolt onto subframe (4 bolts in the rear of housing)
3. S14 case looks to be non-ABS because of no sensor port. S13 case was also non-ABS
4. Output flanges remained 6 bolt except the Nismo diff came with SAME SIZE flanges with a gear on both flanges.
5. Only makes the noise when in gear cruising
6. If I push in the clutch pedal WHILE cruising, the noise stops.
7. Everything bolted in fine, and I spun the front driveshaft part by hand and it spun with no problems.

I plan to raise the rear end off the ground and have someone spin the tires while I look for any rubbing/grinding going on. Only shitting thing is I wont be able to mimic the situation where I know it grinds since I cant put the car in gear and spin the wheels.

Any suggestions?

http://www.youtube.com/watch?v=P4yT9BjYixI

[serge_dk]

actually if you get the wheels up off the ground and put her in gear, then you should be able to see it spin the way it does when you're driving. have someone put it in gear and give it gas and you stand under there (caution) and look for anything you might see.

[cotbu]

Are you sure it's the diff?
Clutch in coasting shouldn't have any effects on diff noise, maybe lighter noise, but not stop. Trans, clutch or drive shaft! Remove Drive shaft if, you cant pinpoint the problem. Do the same test gain.

My stock DS made a sound similar, the rubber bushing was busted causing the bolts to tap on the flange at any speed. S13 Manual

[Luvs2slide]

actually if you get the wheels up off the ground and put her in gear, then you should be able to see it spin the way it does when you're driving. have someone put it in gear and give it gas and you stand under there (caution) and look for anything you might see.

Did you not see the video? The rear was jacked up and that was me taking under the car taking the video. That was in 2nd gear.

[Luvs2slide]

Are you sure it's the diff?
Clutch in coasting shouldn't have any effects on diff noise, maybe lighter noise, but not stop. Trans, clutch or drive shaft! Remove Drive shaft if, you cant pinpoint the problem. Do the same test gain.

My stock DS made a sound similar, the rubber bushing was busted causing the bolts to tap on the flange at any speed. S13 Manual

I'm not 100% sure its the diff, but right before I swapped it everything was fine, no noises whatsoever. I looked at all the bushings, and checked everything while I was under the car. I think the reason it stops when I have the clutch in, is that it is not seeing any kind of extra load from the engine. I'm pulling it tomorrow and opening her back up and measuring the lash to be certain.

[pacotaco345]

Did you check your backlash, pinion depth, and preload when you installed the diff into the pumpkin? This would cause noise if it wasn't set right when the diff is under any kind of load. IE doing anything while the car is in gear.

[Luvs2slide]

No I didn't, and never did it to any of my diffs. Guess I just got lucky in the past. I mean, seriously, other than taking it to a certified rear end specialist, How many people actually check all that, much less have the tools to do so?

[pacotaco345]

I know what you mean, but most people on here don't pull the diff from the pumpkin they just swap out the whole assembly. If you look up "how to set up a differential" though on google there's a few diy's that are pretty good and it really doesn't require that many "special" tools.

[jesse_s13]

No I didn't, and never did it to any of my diffs. Guess I just got lucky in the past. I mean, seriously, other than taking it to a certified rear end specialist, How many people actually check all that, much less have the tools to do so?

Those are bearing surfaces why wouldn't you? Open her up and check and recheck.

[Luvs2slide]

I Took the diff over to MJR and upon his initial inspection, something wasnt right he said as there was some weird noise and the amount of preload it took to spin the front part that connects to the driveshaft. He popped it open and started dis-assembly. There was several issues:

Backlash was not correct...I want to say it was near the toe on front/back of gear (see the picture of the gear markings)
Preload was not right
Pinion depth was not correct either
He pulled off all the bearing froms the carrier and the pinion etc. Come to find out, the main bearings for the pinion were rusted. He said this case was probably left out open in the elements. The noise mainly came from the rusted shit and the noise was amplified.
Also the carrier bearings werescuffed pretty bad too.

http://i76.photobucket.com/albums/j1/luvs2slide/9f321b1b.jpg
http://i76.photobucket.com/albums/j1/luvs2slide/b271eb09.jpg
http://i76.photobucket.com/albums/j1/luvs2slide/a30cffbf.jpg
http://i76.photobucket.com/albums/j1/luvs2slide/3c635c48.jpg
http://i76.photobucket.com/albums/j1/luvs2slide/34fdd5f4.jpg
http://i76.photobucket.com/albums/j1/luvs2slide/f4933af2.jpg

[gostrider]

My diff is making noise too..worst now after the sub and rear diff bushings were replaced...only does in gear not neutral. I have no clue what it is..Is there a rebuild diff kit for LSD 240 diff?

[s13chuck]

i had to take my diff to be rebuilt because of a odd vibration sound on part throttle and decel in gear