Rear end whine!

[DarthMarauder]

I had the dreaded axle wear and 2 years ago decided to finally put in new axles and bearings. The last 2 years the car was barely driven but the few times I have driven it and now that I'm driving it alot more often its humming when the gas is pressed. I'm thinking the pinion bearing got some metal shavings in it and is bad. Was wondering if anyone else has had this problem after putting in new axles and new axle bearings. Also if I were to take the rear end apart to replace the pinion bearing but kept the shims and bolted everything back up the way it was, since the gears are the same and only the bearings were replaced would I have any problems. Or would I have to go through and reshim the rear end????

[4play]

mine has a little bit when your driving around 100kph

[Stranger in the Black Sedan]

I have had pinion bearings not set up exactly the same, and I'm talking, the exact same brand and model bearing (in the case of the 8.8, Koyo High Capacity pinion bearings). You might get lucky putting new bearings in and you might not. I wouldn't chance it. If you got enough metal in the rear to damage the bearings I'd put new gears in it, you don't want to do all that work and still have noise. New real Ford 3.55s can be had very inexpensively on ebay if you keep an eye out, since it's not a desirable ratio.

If you have really good hearing and are picky like me you will always notice *some* noise with a differential. It's just about impossible for a gear driven unit to not hit some harmonics under some speed/load combination. Very slight gears singing under certain accel/decel at certain speeds is going to be almost impossible to get rid of it you have a very quiet exhaust and are really listening for it.

[Blackened300a]

Also if I were to take the rear end apart to replace the pinion bearing but kept the shims and bolted everything back up the way it was, since the gears are the same and only the bearings were replaced would I have any problems. Or would I have to go through and reshim the rear end????

If you pull the pinion out, you'll need to install a new crush collar and there is a torque procedure for doing that. The have to take up the play in the collar then torque the nut and check how much torque it takes to turn the pinion.
I don't think your gears were shimmed up right.

[CRUZTAKER]

mine has a little bit when your driving around 100kph

My 4:10's have had a noticable whine around 35-45 mph.
The KOOKS drone it out for the most part....but they have done it for six years now.

I'm not suggesting you ignore it as I have mine...afterall, I had mine swapped by a guy in PA. that worked out of shed lol.
Mine is obviously fine after some 40k of whup-ass. Just a but whiney.