Gear whine with new suspension installed, pinion seal and aligned

[Andrey Sidorov]

Hey lads, like always nothing goes smooth with my build ahahaha

So recently i have installed Shocks, struts, front control arms, sway bars front and back with endlinks, panhard bar and rear lower control arms on my stang end everything was fine. The shop just installed upper control arm and diff cover as well as fixed my pinion seal leak, also full alignment was performed and pinion angle set.

The issue: Rear of the car whines when touching the throttle at any gear and eventually fades on higher speeds (may be due to car being loud not sure) Whine isnt too loud but noticable

The question is, anyone faced this issue with suspension with poly bushings?, suspension is all adjustable and they set everything. Can it be just poly bushings let the sound go through?, was pinion bolt not set properly?, i provided fluid with modifier so that is out of the question

 

[MrBhp]

What gear are you running? Some are inherently noisy. And yes, harder bushings transfer instead of deaden.

 

[pass1over]

if you just put all new poly bushings in your car and you were used to oem rubber, then yes, you're hearing the increased NVH that comes along with it. And like MrBhp said, some gears are noisier than other. The stock 3.73s in my car like to "sing" a little at certain spots.

Hopefully they replaced the pinion seal the correct way and set the preload properly.

 

[Andrey Sidorov]

What gear are you running? Some are inherently noisy. And yes, harder bushings transfer instead of deaden.

stock 3.55

 

[Andrey Sidorov]

if you just put all new poly bushings in your car and you were used to oem rubber, then yes, you're hearing the increased NVH that comes along with it. And like MrBhp said, some gears are noisier than other. The stock 3.73s in my car like to "sing" a little at certain spots.

Hopefully they replaced the pinion seal the correct way and set the preload properly.

i have oem 3.55s , i will ask the shop the preload question etc, but i know what they will say

 

[GlassTop09]

i have oem 3.55s , i will ask the shop the preload question etc, but i know what they will say

Hi Andrey Sidorov,

Your OEM 3.55 gears are genuine Ford OEM gears cut on the 2-cut face hobbed gear tooth mesh process.......which is the quietest process to date for rear gear mesh when setup is good & shop can't change the gear pinion depth set when replacing a bad pinion seal......only can change the pinion preload on the inner\outer pinion shaft bearings if they overtightened pinion nut after seal changeout potentially causing these bearings to "roar" slightly louder.........IF the pinion nut was overtightened enough to apply more "crush" on the crush sleeve........Ford 8.8" specs call for at least min of 140 ft-lbs to initiate crush on a typical crush sleeve for a Ford 8.8" rear axle. If shop didn't exceed this TQ spec, then most likely they inserted no extra crush on the crush sleeve thus no extra load on pinion inner\outer bearings than what was already there prior seal replacement.............

Don't shoot the messenger.........just giving you the info.........

So, from me knowing this & you've posted that the noise increase isn't very loud in comparison, I'd put my money on the NVH change from using all poly bushings that attach the rear axle to the unibody........

My 2 cents......................

PS--so if you ask your shop anything about your pinion seal replacement, ask what final pinion flange TQ set they applied to flange after seal replacement......they may choose to not answer this but this is the right question to ask to see if they did overtighten this.........

Hope this helps.

 

[86GT351]

Upgraded arms with bushings will increase NVH. If you needed a pinion seal and ran alot of oil out of the differential, they the gear might have a permanent whine now.

 

[Andrey Sidorov]

Update: the same happens in neutral too, revving at stop makes the whine noise higher pitch with the raise of rpm… can be diff still?

 

[86GT351]

Update: the same happens in neutral too, revving at stop makes the whine noise higher pitch with the raise of rpm… can be diff still?

If the noise is there when sitting still in neutral and revving it cant be differential as it is not turning.

 

[Andrey Sidorov]

If the noise is there when sitting still in neutral and revving it cant be differential as it is not turning.

Ok that’s a concern then , when idling the noise isn’t present but when reving (sitting still at stop) it’s there, wth could they do there in the shop hm… forgot to mention trans mount was changed too

 

[DieHarder]

Just my opinion but if you're not satisfied take it back and ask them to get it up on a lift and try to recreate the symptoms to see if you/they can pinpoint where the sound is coming from. If the same sound is present while in neutral it's not the diff.

Other options you can try is switch out some of the parts and note differences in NVH; from your description I think I'd start with the trans mount.

 

[MrBhp]

Power steering pump?

 

[Andrey Sidorov]

Power steering pump?

Just my opinion but if you're not satisfied take it back and ask them to get it up on a lift and try to recreate the symptoms to see if you/they can pinpoint where the sound is coming from. If the same sound is present while in neutral it's not the diff.

Other options you can try is switch out some of the parts and note differences in NVH; from your description I think I'd start with the trans mount.

Hopefully, its frikin freezing on east cost today, tomorrow will try to stethoscope the sound hopefully, and then will bring it to shop

 

[Andrey Sidorov]

So update, noise appears when you pressing gas, unless clutch is in, how can trans be related to it, coinsidence? , trans mount was changed tho

 

[OX1]

Poly trans mount?, that's probably your answer. If not, maybe trans input bearing, but that would be awful coincidental if noise came from bearing, right after susp/mount work.

And on rear control arms. I went with the Roush upper/lower for that very reason, as I did the poly and/or solid bushings on my fox Capri, back in the day, and NVH went up a lot. I have zero wheel hop, and while I did not cut 1.5's for 60's, I didn't cut 2.0's either (think my best was a 1.71, but acceptable to me for a rear susp that had zero increase in rear diff noise, and zero wheel hop even on the street).

 

[Andrey Sidorov]

Poly trans mount?, that's probably your answer. If not, maybe trans input bearing, but that would be awful coincidental if noise came from bearing, right after susp/mount work.

And on rear control arms. I went with the Roush upper/lower for that very reason, as I did the poly and/or solid bushings on my fox Capri, back in the day, and NVH went up a lot. I have zero wheel hop, and while I did not cut 1.5's for 60's, I didn't cut 2.0's either (think my best was a 1.71, but acceptable to me for a rear susp that had zero increase in rear diff noise, and zero wheel hop even on the street).

The noise itself doesnt bother me, what bothers me is that i dont know if its due to just bushings or something is really wrong lol, im ok with noise. i dont think its poly, was oe replacement not ford one tho

 

[JC SSP]

I will throw my .02 cents...

True harder suspension bushings will result in increased NVA, but a new gear whine seems a little strange. High milage drivetrain (don't know your car's milage) will yield some noises, so maybe it is increased NVA?

If I were a gambling man... diff cover as well as fixed my pinion seal leak, also full alignment was performed and pinion angle set. This is where your issue might be coming from.

Did they use the right rear end fluid, friction modifier? Also was preload and pinion angle set correctly. Once you confirm these then you can move on to another possibility.

Heck if the noise is minor and you can live with it, just turn up the tunes...

 

[MrBhp]

If the noise is present when you're sitting still, I find it very improbable that the cause is anything rotating from the input shaft rearward. Unless you have multiple issues. If, like you said, it happens when stationary, the problem is under the hood.

 

[Midlife Crises]

Stationary, with engine running and clutch pedal out. The tranny input shaft and cluster is turning. Noise will come right up through the shifter. Push in the clutch. Does it get quieter?

 

[Andrey Sidorov]

Stationary, with engine running and clutch pedal out. The tranny input shaft and cluster is turning. Noise will come right up through the shifter. Push in the clutch. Does it get quieter?

If the noise is present when you're sitting still, I find it very improbable that the cause is anything rotating from the input shaft rearward. Unless you have multiple issues. If, like you said, it happens when stationary, the problem is under the hood.

The noise appears when applying throttle only - in neutral and in gear, stationary and while driving
If clutch is pushed in, there is no sound,
also no sound if you just idling or coasting in neutral without applying throttle (at least i dont hear it cause drivetrain is loud)
Hella weird lol