Stkjock

a little noise on decel is typical, as long as its decel then you should be fine

JDWalton

I bought from brenspeed, there FRPP 4.10s and I used Royal Purple gear oil. So far my break in is such.
The quick test drive the guy at the shop did. (1 mile?)
20 minutes
5 Mile drive I did, babying it
40 minutes
5 Miles drive, babied
30 minutes
25 miles highway, easy on gas (just cruise control at 65 in 5th)
1 hour 30 min
25 Miles highway, same
30 minutes
5 miles home

Through all off this, going easy on it, sounds fine under acceleration, its under neutral load or slowing by engine that i hear it. It is worst going from 45 down to 25, much more pronounced, though I can hear it at higher speeds too.

05fastblk

i still have my 4.10s in the box but when i had the install 3.91s on my 350z i had little whine for about a day but it dissapeared next morning. Just be easy on it for a while, it will be worth it in the long run.

BruceH

Delete...

JDWalton

What is this whirring noise?
Whirring noise only while decelerating at any or all speeds is most likely caused by bad pinion bearings or loose pinion bearing preload, and almost never by bad ring and pinion gears.




Seems to be what best fits mine. so whats the deal with this, they will have to rip it apart and rebuild again if this noise doesnt go away after a few hundred miles? It just really pisses me off. i'm not a mechanic, but I follow instructions really well and everything I have done has come out right.... for once i choose to have it "profesionaly" done and it comes out messed up. From what I have read, I did everything right so that installed properly should not have any noise. So instead of spending the money and buy the tools myself, it was sopposed to be just a little more expesive to have them do it, and I wouldnt have to work out in the cold, laying on the ground again.... This is a shop that others in my family have used for years, I just hope they do the right thing when I bring it back into them. Short of that, if any noise continues, I'm gonna bring it to a Mustang shop up in mass, and then go after this place in small claims. Oh well, guess I'm getting a bit ahead of myself, just upset, first thing I havent done myself and it comes out messed up. If I mess it up myself, I wouldnt even be this pissed, casue I didnt pay to have it done, and wouldnt be surprised having never done it.

JDWalton

So I brought it in this morning, the tech went for a ride with me, said he hears what I'm talking about, was gonna take it in. The guy doing the schedualing and stuff that kinda runs the show stepped in and asked me to put another 150 miles on it. The tech said it could be the paint he put on to check the meshing of the gears.

I looked up the backlash spec and it looked like .008-.015 but when the tech had shown me he had just checked for back lash, he showed me by pushing up and down on the gear what looked to be about 1/8" Also, when I asked him how much shim it ended up needing the response was, "oh, I didnt really keep track of the shims" well see if the extra 150 miles helps it. I wouldnt put money on it.

JDWalton

This isnt just a track car, and from what I have read and others have said if done right there should be NO sound at any condition. TBH I havent even taken it to a track, this is a fun car for me to drive around, and back roads are a blast, however hearing an annoying whine everytime I am throttling down into a corner is simply unacceptable.

Argonaut

From my experience riding in a number of different cars - for every person who says they have NO gear whine, there are an equal number who have *some*. I've had two sets of gears in a Mustang and both whined a little (and I really mean a little), they were both more noisy than stock. But it was so little that it never bothered me or any passengers. On another install I had a lot of whine, took it back to the shop and got it fixed. So, I don't know that you will ever get it as quite as stock...maybe so, maybe not. YMMV.

JDWalton

yeah, I expect to here a little different noise, as the gears are turrning faster in there for the same output, but this is to the point where even with my radio turned on and at resonable volume, I can hear the gears in some spots over the radio.

MELLOWYELLOW06

I have to hear my kids whine all the time and its not just at 45 mph, its all the time, and no friction modifier will help that . These little noises are so minor and we keep reading about them that as soon as we install we actually go and listen for it. Between my exhaust blower and stereo, I cant even tell if I have a whine. But if u r hearing something bad, note it to the shop asap so u can have some recourse. Enjoy the kick.