After the installation of my ford racing rear lower control arms I get some whining noise from the rear diff but only during right turns / curves. Driving straight or even durnig left turns there is nothing, at least that I noticed.

My 3.31 gears were installed a couple weeks ago but there was no noise, it started after the LCA install, any ideas?

 

Any idea? Is it because the suspension is now to stiff, limiting the movement of the axle, driveshaft and so on?

 

This is a weird one. Did you install the LCA's?

 

Yes, I did. Why? Choose the FR LCAs over any other cheaper ones not to get any issue and now this. Weird!

Today I will try to install them 180 degree rotated (inside facing outside), maybe it is an alignement issue. Maybe this moves the axle in the right direction?!

But why didn't it show up before?

 

American Muscle has a good install guide http://1.cdn.lib.americanmuscle.com/files/50157.pdf (if this link works.) I installed mine 'myself' without any problems.


Did you add 'friction modifier' to your gear lube when the 3.31's were installed?

 

Friction modifier was added for sure. Just checked and reinstalled the LCAs, not sure but I think the right wasn't correct. Have to try that tomorrow.
Had a hard time getting everything back together, the axle shifted backwards and I had to use some brute force to get the bolts back in!

 

O.k. took it for a test ride, but no change still that whining during turns. Guess I have switch back to stock to check 😟

 

Keep us posted on how it goes

 

I have noticed some of this since installing a Steeda upper control arm. It's hard to say if we're hearing the same thing but I suspect that there is always some noise/vibration coming from the axle assembly. The soft bushings on the stock components presumably damp-out much of the noise. Your new hard bushings are allowing more vibration (sound) to get through.

There is a TSB about diff noise saying that the high performance LSD in these cars makes noise and that some sound is normal.

 

I had the same idea but it isn't there all the time that is what makes me wonder. I'll have it all checked next week, there is another vibration at certain speeds and that 's adding up. I am not sure what is causing all this, maybe one or both rear brake rotors are warped. A mechanic told me last time that the left one has an unusual pattern.

I think it is a good idea to replace the rotors and the axle bearings to eliminate every possible cause of noise or vibrations, what do you guys think?

 

Update!

It looks that both axle / wheel bearings are bad. There is quite some play in both bearings left side worse than the right side. The noise is getting more and starts to be present at any driving condition 😒

 

Yikes!
Very glad to hear that you got an answer.

Is this covered under warranty?

 

I hope but I don't really think so. It appeared after the rear gear change and I hope that the company that did the install at least pays for the work time?! Let's hope for that...

 

Ahh...I see.
Good luck! Pleas keep us posted on your progress.

 

Update!


o.k. the whining noise during the turn is gone but I know have a constant noise no matter what I do. They told me that it would be because of the gear change and all the mods I did. All those firmer bushing would transmit the noise from the rear diff but I don't know. Could that be??? Any ideas?
I think about replacing my Ford racing rear LCAs with the stock ones to see if that is really the case.


And the really bad news is, they made me pay almost 400 for parts and new oil. That sucks...

 

When I had my whiteline upper control arm installed, I was surprised how much louder the gear whine was. Then I had to remind myself the reason why I bought the base GT TrackPack. Performance! After I drove it a little while, I didn't care anymore. The car handles sooooooo much better.

 

O.k. That makes sense but why is the fr 3.31 rear gear that much louder than the stock setup? The improved performance is a point but the long distance comfort is a different story. I have to see about that ...

 

Yes, firmer bushings will most certainly increase noise and vibrations. That's the price to pay for such parts, and that's why Ford uses softer materials - to avoid transmitting vibrations into the cabin.

 

If you ever drive a vehicle with solid engine mounts, you'll know exactly what I mean. The vibrations are unreal, and it'll make you go deaf...