Rear Axle Bearing Noise

[Berlioz101]

Good Afternoon/Evening/Morning everyone,

I have had my 2011 GT auto rear end completely rebuilt after very bad howling/grinding/whining, you name it. Old 3.15 Gears were replaced with 3.31 gears, axle bearings, seals replaced too.

One of the sounds aside from the diff howling was coming from the right aft side of the car, it didn't sound like a "whine", but more like "eeeee" that changes in pitch (onomatopoeia) with the speed, and continuous, not cyclic in nature. Think of tire noise, but higher pitch and more metallic sounding and continous, not a grinding. It was very noticeable before the axle bearing replacement and the entire rebuild. After I got the car back Friday (5 days ago), it was completely quiet from what i noticed/paid attention to. After driving around for the next few days, I was able to hear the sound coming back, although above 40 it gets drowned out by road noise until I decelerate. It isn't exceedingly loud, and unless you're listening carefully I don't think it would be noticed until about 20mph and decelerating or accelerating, without music on, but its audible over the AC if below the bottom 1/3 of blower strength. (It is NOT loud, but If you were told to listen, you should be able to hear it)

Does anyone know what this noise could be, and how to fix it? It's not a "howling" or "grinding" or anything, but it sounds localized to the right side of the car when I'm in motion, regardless of if I'm in gear or braking, turning, etc.

 

[Berlioz101]

I replaced the OEM diff cover with the ford racing girdle before I took it into the shop.

I've lifted the car and replaced the differential fluid. Here are some of the facts:

1. There was approximately 2.1 quarts of 75w90 in the differential.
2. Illustrating what the differential fluid looked like: pea-soup green with honey floating in it, or green mustard color, not texture. didn't try smelling it but being close to the drip pan, i couldn't smell much.
   1. is this normal? I've heard that different brands of diff fluid come in different colors, but this literally looked like soup.
   2. Example: https://cdn11.bigcommerce.com/s-fn8...57_4347041891988974_1236182798341399067_n.jpg
3. The Axle assembly and the outside of the differential housing were not cleaned.
4. the differential fill plug was not cleaned off. there was an extreme amount of metal shavings on the magnetic fill plug. I recorded it prior to, and after cleaning.
5. the differential breather valve was dirty as hell. cleaned and replaced.
6. refilled with 3qts 75w140 with additive mixed in from the factory.
7. utilized Teflon on all 3 opening plugs (front OEM fill plug, ford racing girdle fill plug, ford racing girdle drain plug).

After a quick test drive (literally about 3 minutes), noise seems to still be present & still localized on the aft right side of the vehicle. I'm going to give this time to lube itself, but how long should that typically take? I've read that it lubes itself in turns but I don't know the exact science behind the wet hub assemblies.

My opinion: Either a poor job was done or an incomplete job was done. Shouldn't shops clean off the things they're working on? I paid for degreaser on the itemized bill but itdk what it was used on; it's clear the axels were not cleaned. was I expecting something that I shouldn't be? I want to know if I'm out of line to cage my expectations but... This should not be happening after a week of having the car back, and on top of that only four-days worth of driving. Something is awry.

 

[rocknrod]

Ya sounds pretty shoddy to me work wise. Does it mean the actual job wasn't done correctly? Who knows.
I would pull the axle and look at the bearing, but that's just me.

 

[GriffX]

Probably: Backlash too small, lead to a whirring sound at low speed, probably louder on right turns, lots of metal in the oil.
(Ask me how I know )

If you drained the oil just with the lower plug of the cover, some of the metal is still inside, there is a pit which is deeper than the plug below the ring gear.

AFAIK: No need to add teflon tape to the plugs, they should be have a conical shape?

 

[86GT351]

Simple question. What did the shop say that did the repairs?