Noisy Rear End

I doubt that it's your driveshaft and your description doesn't make me think U-Joints. My guess is that your ring and pinion gears are worn. May be time to go ahead and have those 3.55s you've always wanted installed.

Like said it could be your gears or maybe your fluid is pretty old or leaked out. If it's worn gears I would be ready to add some 3.73's. (maybe 4.10's since you have an aod)

check your diff bolts to make sure its not loose.

Okay man here we go.

I just had this problem with my 4.10's we installed.


When installed WITHOUT SHIMS (behind the pinion) we heard a nice whine sound and tumble sound. When putting it into gear it would go in not as smooth as before. When down shifting it would really whine and make almost like a clunk noise.

Here was the problem.. With no shimes the Pinion was not spaced correctly. So under excelartion it had the correct angle,(thus just a little bit of whine) but under de-celeration the pinion would almost bounce around (because it was loose and not fully tight). We thought it was the gears.( Because the old 3.55's had no shimes). Bought Richmond 4.10's same problem. So after talking with several people we found out the following......

Ford gears are shimed on the Pinion. Not a very large amount, we ended up putting in a .17 Shim and a .13 behind the pinion and infront of the bearing. Installed the pinion and gear.. When rotating the wheels it was WAY too tight. So we removed the shims and added a .24 shim. Rotated the wheels and they moved as they should.
As soon as that was done and adding ALL that damn fluid in AGAIN (3rd time), i started rolling. NO WHINE NO TUMBLE SOUND AT ALL !!!

So you might wanna make sure you spaced the pinion correctly.


( i hate the smell of Rear End Gear Oil )