Rear End Whine

[CWizard]

I recently noticed a high pitched whine coming from the rear under load. It's clearly there in 3rd, 4th, & 5th, maybe the lower gears too. But since it's not real loud I may not hear it over engine noise. Doesn't vary with rpm and seems to depend only on whether there's a load on the drive train. Gas on, whine; gas off, no whine. It's a Tremec TKO 600 and a Ford 8.8 rear end with 7000 miles. Started noticing the whine at about 6500 miles. Where should I start looking?
Thanks.

[blykins]

If it's off and on like that....My guess is that your backlash/pinion depth is off a little bit.

I'd yank the diff cover off, paint the gears and see what the shape comes out to be. If you have a mag base and dial indicator, you can check the backlash as well.

There's a possibility that it could be a bearing going bad, but chances are the gear mesh is the culprit here.

[JAM1775]

I had whining 373's swapped to 327's, no whine, then later went back to the steeper 373 gear. On re-install to date no whine. The explanantion given by the shop that did this work was gears will whine if the bearings are not pressed in properly .(?). Far from my expertise but it was fixable !

[ZOERA-SC7XX]

Too much play/end float in the pinion shaft and/or improper backlash. Could be caused by a bad pinion brg.

[trularin]

Take it to ring and pinion shop and ask them to check the gear setup.

[cobrajam]

I have experienced a lot of whining coming from the rear...are you sure your wife is not in the trunk too.

[zipzip]

Whine in a spiral bevel set is almost always from contact pattern. A bad contact pattern may come from too much backlash, but the pattern is the key.

see pg 18 of http://www.arrowgear.com/pdf_files/catalog.pdf

Take the suggestions and double check yourself, or bring it to a reputable shop. I've found that a lot of times a local drag racer will be better than a "mechanic" shop.