[jannisa]

Hi all
I recently installed a quaife lsd that was already modified in exchange pumpkin by Birds UK. I notice that when I deccelerate (no throttle applied at all) from 105km/h to 90km/h I get a very subtle whining/rumble/whistling sound coming from the diff. Same while accelerating too in that range of speed but even more quiet. Mind that I decided to take the route of the (unnecessery officially) breaking it in for a thousand km and the sound is indeed very subtle, you might say even hardly noticeable, but it sure is there.
Has any kind fellow noticed anything similar or any difference whatsoever in the operational sound of his lsd?
Thanks

[enrita]

Nope my quaife is very silent. Strange sound are due to bad installation.

[jannisa]

Ciao Enrico. I had everything checked several times regarding installation and what surprises me is that my final drive was delivered already installed by the pros in UK so failure risk should be minimized (shouldn't it?).
"Very silent" as you state means that it is any different at all?

[enrita]

Yeah my quaife has no strange sounds whatsoever. Did you try to contact birds?

[jannisa]

I did and they were always prompt but their recommendations didn't solve it. They suggested to check a few things which I did and were ok but the noise persists and proposed to leave it as it is and monitor how it evolves. Anyone noticed something similar?

[Bimmer This]

sounds like they adjusted "backlash" wrong.

[e93WhiteonRed]

Yeah - lash, backlash, and pinion depth. Bad install dude... They probably just slammed everything together and didn't check the contact pattern of the teeth - usually you have to shim them properly...

[Bimmer This]

Originally Posted by e93WhiteonRed

Yeah - lash, backlash, and pinion depth. Bad install dude... They probably just slammed everything together and didn't check the contact pattern of the teeth - usually you have to shim them properly...

you got it!!!!!

[scheherazade]

My wavetrac sounded like stock. No new noises.

The only difference I could hear was the "stereo" sound of both tyres in the rear breaking loose together

-scheherazade

[creaminz]

that's the noise i'm hearing!! i just wasn't sure if it was coming from Quaife LSD or some boost leak. It can only heard on the freeway going +65mph and i let off the throttle about half way I hear this whistling. loud enough that my wife can hear it. I bought bunch of silicone hoses, intercooler hoses, even purchased new DV to see if I can find out the problem. I hurt my finger few days ago and also waiting for my ratchet to come in...I report back once I can use my hand again to see if it was indeed boost leak or LSD.

[jannisa]

Thanks guys for all inputs. It seems that this sound was documented already :
http://forums.bimmerforums.com/forum....php?t=1509515

Creaminz, sorry to hear you had to go through all this.
I will contact Birds again tomorrow and I 'm sure Kevin and James will address that.

[Eyeman]

I get the exact same humming, practically only noticeable at 60-70mph. I assume it's there at slower speeds but it's quieter and at higher speeds you can't hear it due to road noise. You basically hear it when the differential is not pulling and I'm sure it's a slight shimming issue. My shorter wheelbase 135 with no rear seat probably makes the noise easier to hear in my car.

Mine was silent for a few hundred miles and got louder for a few hundred but now seems steady. If it bothers you or you think it might cause wear problems down the line then get them to redo it but I don't think that it means they did a rush job. It's just too common and I think it's reasonably likely you'll get this noise unless you get "lucky" and get a perfect install. I had my installer listen to it and now if I get a problem with wear or something way down the line they'll cooperate with replacement.

[moveswiftly]

I have the same noise. I don't think it's anything major.

[Bimmer This]

nothing major, only annoying.

[dbjb]

Anyone experience this with a Wavetrac or just Quaife?

[Mr. 5]

Originally Posted by Bimmer This

sounds like they adjusted "backlash" wrong.

Agree.

[Mr. 5]

Originally Posted by dsbj

Anyone experience this with a Wavetrac or just Quaife?

It's not the dif. It's how the back lash was measured.
It's install error.
BUT, it's nothing major. It's mainly just a sound and nothing more.

[e93WhiteonRed]

Depends - It really comes down to the contact pattern. If the gears are contacting eachother too close to the end of the teeth, it will eventually round off the teeth, increase the lash play, and under very stressful lunches it could break some teeth if there is pinion deflection. Honestly though - thats more for 450 hp drag cars lunching with slicks - I'm sure you'll break something else before that happens, but it is a possibility...

[jannisa]

UPDATE : SOLVED

Per the recommendations of Kevin at Birds UK I had today the castelated bihexagonal nut that controls the bearing pinion preload untightened slightly per 8 degrees approximately (counter-clockwise). Mind that during installation this nut was not touched at all and my original exchanged pumpkin that was checked by Birds was found tight in the pinion preload too, I don't know why but anyway. That was the original recommendation to cure the issue of noise but both my mechanic and me were reluctant at first to risk with the preload, well executed today (scary? I got s&it in my socks before the test drive) but thank God everything is running smooth as it should now.
Allow me to thank Kevin Bird here on the forum, the guy was replying to me even late at nights and a Saturday too, I suppose the reputation of his and James' shop is by far not a coincidence.
If any other explanation is needed for anyone concerned feel free to ask.

[e93WhiteonRed]

That nut is what holds the pinion in the pumpkin. I dont think you can just re-tighten that because there is a one time use crush collar on it... unless I am incorrect...

[jannisa]

It 's the nut that controls the pinion preload. It is removable and adjustable even according to BMW TIS. You first have to mark where it was originally set though.

[Mr. 5]

Originally Posted by jannisa

UPDATE : SOLVED

Per the recommendations of Kevin at Birds UK I had today the castelated bihexagonal nut that controls the bearing pinion preload untightened slightly per 8 degrees approximately (counter-clockwise). Mind that during installation this nut was not touched at all and my original exchanged pumpkin that was checked by Birds was found tight in the pinion preload too, I don't know why but anyway. That was the original recommendation to cure the issue of noise but both my mechanic and me were reluctant at first to risk with the preload, well executed today (scary? I got s&it in my socks before the test drive) but thank God everything is running smooth as it should now.
Allow me to thank Kevin Bird here on the forum, the guy was replying to me even late at nights and a Saturday too, I suppose the reputation of his and James' shop is by far not a coincidence.
If any other explanation is needed for anyone concerned feel free to ask.

This is a little sketchy.
Can someone show us where exactly it is because if it's what I'm thinking, this shouldn't be one of those things to just loosen.