Hey guys, so I installed SPL solid diff bushings as well as a 3.3FD about 4 months ago. I have been noticing a noise, I am pretty sure it started right after the install, but I can't be certain. It is like a woowoowoo noise from the rear, and it occurs when in coasting neutral at high speeds, coasting with clutch pushed in at high speeds, and also when I am in first gear and I let off the gas at low speeds 5-15mph.

Hopefully it is not bearings in the diff..... could it be just the diff noise is amplified due to the solid bushings? I was originally thinking rear wheel bearing, but I don't think I would hear a woowoowoo noise at such low speeds if it was.

Any input appreciated!

 

was your new gears/lsd shimmed properly?? When my new LSD was installed for the first couple hundred miles I had the same noise you describe. Once it was broken in and did a fluid change no more noise.

my installer said it could make that noise if not centered properly so he checked it when he did the fluid change. didnt change anything but it went away so I guess it was just it breaking in

 

I just swapped the whole 3.3 pumpkin from my friends automatic 350z, do you have solid bushings too? I changed the fluid with mobil 1 synthetic, I wonder if that could be causing the noise.

 

solid bushings and diff brace

 

Hmm, and you hear no such noise at highway speeds when coasting?

 

no whine any more... but I have allot of other noises since my trunk is stripped out and I have a CF hatch so on the highway it would have to be pretty noticeable for me to hear it.

I had that whine you describe before and I dont have it now... I will be racing the car on saturday soo I will be sure to try to listen on the way to the track to see if I notice anything at all.

 

i have a 03 base with open diff and installed the solid bushings and i know EXACTLY what noise you mean. dunno why but mine happened after the install also. does it matter if the axles are bolted up in diff holes than they were before? like they arnt balanced and have to be bolted up in same holes do they?

 

mmmm no axles shouldnt matter I dont think, I was thinking the driveshaft may be imbalanced, but i unbolted it, rotated it, and it still makes no difference....

Maybe its normal? Im glad someone else has this problem at least.

 

hmmm i asked my buddy who is a mechanic and he said its pretty common for manuals to make those humming noises. idk i feel no issues so im ok with it

 

Hmmm, so is your humming or like a wooowooowooo? Mine is like wooowooowoo, like a rotational noise.

 

if im lightly on gas or coasting i can really hear it good. and the noise changes in volume when i go from lightly on gas to gradually pressing it. its def a woo woo woooooooo.woo it can do a long woooooo if my foot doesnt change on accelerater but when i let off it woo woo's

 

Sounds about normal

 

YES THIS! exactly.

 

You think this is normal for solid bushings then? Do you have this problem too?

 

i have the same noise. can really hear it at moderate gas, such as going on 360 degree off ramps and stuck behind traffic.

 

Not really a problem, started hearing it a little with my rear bushing replaced. Then it got louder with the front bushings and LSD install.

 

I have it. The aluminum bushings dont isolate the noise like the stock rubber bushings but actually transfer it to the car, making the noise appear.
I thought it was the shim specs on my new KAAZ lsd + 3.9fd and had it re-shimmed, but that only changed the noise slightly.

 

+1.. its just nvh.

totally normal. end of story.

 

sweet! after you think about it, it all makes sense. no rubber bushing to isolate/quiet the noise. thanks!

 

I am happy this thread happened, I did my spl diff bushings about a month ago, and I thought I messed a bearing up. I am probably going to go under it this weekend and do a re-torque on everything just to be on the safe side