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Gear Whine after Whiteline rear upper / lower arms installed

So I've installed my whiteline lower rear and upper rear control arm. Immediately after the install, I noticed that there is now gear whine coming from the rear diff. I was already expecting some increase in NVH but I wasn't expecting things to get this loud. It's not TOO bad, but it's beginning to get a bit annoying. I hear it while on throttle at all rpm's in higher gears, so freeway cruising etc. Throttle off = no noise. Any amount of throttle = medium to high pitch whine coming from the back. Normal driving on the street, I do not notice it unless I'm up in 5th.

I had the installer look it over, and there's nothing rubbing etc. Pinion angle looked good. Had the dealer look it over while the car was there for something else, they too said everything is up to spec settings wise and pinion angle wise.

With how nice the car handles now compared to before, I'm willing to live with it but I'd love to get rid of some of the noise if possible. Has Anyone else noticed gear whine from their rear arm installs? Perhaps it's not normal, I do not know for sure (have not had a chance to compare with any other boss 302 on similar suspension setups).

I'm going to add some dynamat material under the rear seat in hopes that will help a little. I have heard that our diffs / final drives are noisy anyway, and stiffening up the rear will only make noise and vibration more noticeable.

Any thoughts, ideas etc? Should I be at all worried about possible extra wear and tear on the rear end, gears or driveshaft etc?
When I installed my UPR brand UCA, I noticed the gear whine too. I also noticed a little clunking noise which I believe is the backlash in the gear set. I always check the gears for wear when changing the diff oil which I do every year. No wear at this point and I think I am around 13,000 miles. I got use to the extra noise at this point. The control arms you installed are not making the noise; the noise was all ready there. The arms arm just transmitting the noise now and I would consider it normal. I have also heard some arms are better than others at NOT transmitting noise.
The whine from my gear is the only thing I don't like about my Boss. If you didn't hear it before, I would remove the UCA to see if the noise goes away. The whine it terrible!
It's improved communication between your car and you. ;D. Most likely there is nothing wrong and most of us have experienced similar noises when making suspension upgrades.
I am ok with it as long as it's "normal" .

I just wanted to hear from others to be sure it was.

Yeah I'm surprised how loud the rear end is. I've gone through super lightweight clutches, flywheels, carbon shafts, 2-way locking mechanical duffs on a few old projects and expected this type of noise from those upgrades simply due to their nature. I wasn't expecting a stock setup to have this amount of noise. I guess I know why ford left the sloppy oem arms alone, as they masked how the noise transferred to the cabin.

I like the way the car drives now more than the sound bugs me, thanks guys I have my answers :)

Grant 302

basic and well known psychic
Sounds perfectly normal to me, Tony. I could listen to it this weekend if you still have any concern. Swapping any one of the links in the rear PHB, LCA, UCA will transmit diff noise to the cabin. I do not think mats will dampen the noise at all since these are direct connections to the unibody and there is no way to insulate against them. Fresh fluid may help a very small amount.

Personally, I think the best way to stop it from bothering me was to increase the exhaust volume!
Yeah I figured it was normal, and somewhat expected. But doesn't hurt to ask to be sure. I was mainly concerned about possible extra wear and tear and warranty issues etc.

I guess I will try to dynamat under the rear seat a little see if that helps a tiny bit.
Hello WFZ - My first thought when seeing your post was whether you have one of the new updated WL UCAs? I had one of the first generation ones that began to crack after just a few days of hard driving.

After replacing it with a Steeda UCA and bracket, I was getting some gear whine at 75-85mph that was really annoying but I lived with it. Once I installed my Dynotech driveshaft (not DSS, it's a Dynotech courtesy of [email protected]), the noise went away completely. We didn't touch the pinion angle at all, by the way.

Good luck!

I think its normal. I installed BMR upper, lower control arms and upper mount, and I have much more gear noise since. It is anoying, but I'm getting used to it. I put some Hush mat in my spare tire well and and trunk space and it helped a bit, but not as much as I wanted. If you tap the spare well it sounds like a drum, so I thought it might help dissipate the lower tones which I "think" it did.


Lord knows I'm a Voodoo Child
Exp. Type
Time Attack
Exp. Level
10-20 Years
NY Metro
Ford put that squishy bushing in the UCA because of this sound. 3.73 gears are very prone to whine and when you get more solid with rear axle connections they act like a tuning fork and transmit the sounds and vibrations to the chassis structure. Not much you can do with it.


Same issue with Ford Racing lower control arms (poly) and relocation brackets. I figure these make nice amplifiers being round hollow tubes. Noticed an increase in the clunking every now and again as well. Feel of the car is definitely worth it for me.

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