Rear gear change out help...

[vr1967]

I regeared the rear of my 96 C3500 SRW from 4.11 to 3.42 with a new US Gear ring and pinion. Replaced bearings etc. On setting up the pattern, everything looked good and is within spec. Even had a mechanic friend look at it.
I have a whine though, but only on coast. No sounds during acceleration, etc, just when I let off of it. We pulled the cover at 300 miles to check, and everything looked good. I now have about 1K miles on it, with the same slight whine on coast. Thinking of pulling the cover again to look if I can find posi additive locally.

I have never used aftermarket gears before, but I couldn't find any 10.5 3.42 GM gears, so could tis be where the slight whine comes from? Am I missing something?

Thanks
Virgil

[crashz]

I re-geared my 83 (same FF rear axle) and set it up by pattern alone and got no whine, but this is with a set of used gears.

My thought is that the gears may be wearing in or you have the preload to tight (to much drag) or to loose (not enough drag). Fortunately the 14 bolt FF is easy to adjust the lateral movement of the carrier and ring gear with the adjustment rings, so slight adjustments are easily made. If the grease pattern is good and centered on the ring gear teeth, the pinion depth should be OK.

Have you called the gear manufacture to see if their is a break-in period?

[Robyn]

How was your backlash??


Missy

[JohnC]

Forgive me if this is a stupid question, but did you check the contact pattern in both directions? If it's good, and the noise isn't too distracting, I'd let it go.

Otherwise, talk to the vendor. (If the drive pattern is good and the decel pattern is bad, talk to them, too.)