Topic: Gear Noise

[vikingsven]

I just installed a new detroited V6 diff in my truck and noticed a distinct whining noise coming from the rear end. The gears are used V6 gears (4.10) and all other internals are new (bearing, etc.) The noise only occurs when there is a light load on the drivetrain (ie: 1/32th throttle). I cannot hear it when I'm on the throttle or coasting, only when I'm barely touching the gas. The higher the speed, the louder and higher pitched the whine. There are no unusual detectable vibrations. The gears were professionally setup and everything 'looked' fine before it went in. Does anyone have any ideas on what might be causing the whine.

[vikingsven [OP]]

Anyone??

[BigMike]

Did they preload the carrier?

Any used bearings used?

Defective Detroit?

Heres a good one, did they re-add some gear oil (!) ?

I think its all a shot in the dark, but good luck.

What about backlash? Was it built to tight?

You say they are professionals; Have you had other diffs setup by them without any problems? What do they say when you bring it back in and claim its making noise. Any good shop will tear into it and fix it since the noise was not there before they installed your locker.

Let us know what you find out,
Cya,
Mike

[vikingsven [OP]]

Ok:
New bearings throughout
Brand spakin new detroit
New oil
Backlash and preload set to specs.
(Used gears) ??Hum??

The guy that did the setup is a family friend with many years of mechanic work with PG&E. He's a good wrench and I trust his word and judgement. I dropped the diff in the axle with no problems and filled it with new oil. He thought that something may have worked itself loose or perhaps the gears were wearing in a sightly different pattern being that the whole shebang is riding on new bearings and carrier. I thought the same thing, but I'm no expert when it comes to gears. I guess I tear it down and have him recheck everything this weekend.
Any more thoughts

[BigMike]

Yeah, I think I would go back to the source and have him examine it. After all he's the one with your $$ and its promise of a good job.

[vikingsven [OP]]

Well: I took it apart and had it looked at. Everything was still ok, but we backed the pinion off the ring gear to increase the backlash. The noise has subsided substantially and I can hear myself think again at speed. I guess I would have to get a new set of gears in order to cure the problem entirely. Go figure. Hey BigMike, any specials this month or in the near future??

[cruzila]

What kind of a pattern did you get? That would make the difference. Backlash should not do that much.