4.77 on the left, 4.57 on the right


4.77


4.57


As mentioned, 4.77 shouldn't whine like the 4.57. Mine would whine VERY softly under light throttle input at 5,700rpm or so.

 

Diff noise is usually caused by worn gears that have a poor contact pattern, or a set of new gears that was not properly set up. Too much backlash, incorrect coast/drive pattern. Here are a few examples of what a contact pattern should look like. They can be checked very easily if you just follow the shop manual

 

NICE! Love the schematic!


As for the whine, I had 4.57s and I hoped they'd quiet down over time. They didn't. I had to add sound deadener to have the wife ride in the car and wear earplugs for road trips. When the diff blew, I was actually happy to get back to OEM quietness. I hear the 4.56's are better, though.

 

spunkysandoval Posted on Aug 26 2007, 05:12 AM
It's a little too easy to state this and be done with it.
Some gears whine by default / design, even when the setup is spot on.
The Richmond 4.57's with the 7/32 whine, no matter how you set them up.
Mine do, at the revs Slow mentioned (in 6th gear I might add)
The Richmond 4.56's, with the 9/41 are much closer to the OEM gears (10/41) and as many have mentioned will whine much less IF set-up correctly.

If you can't get the correct contact pattern by changing the backlash there's nothing else to do but to take the diff apart and change the shim, because the pinion will be to deep or to shallow as mentioned in the pics.
Not that easy IMO

 

Just say you supercharged your rear diff.

Getting 4.57R's we will see then. I'm sure they will whine and that will be my excuse.