ok, 2 days ago we did a gear swap in my buddys truck (stockgmc), he went from a 3.42 to a richmond 3.90. we made sure that everthing was set right and the wear pattern was dead in the center so we are positive everything was done right. they whined like a typical aftermarket gear would especially when off the gas just coasting but they sounded quiet when on the gas and we knew they would whine some but all of a sudden today he wanted me to ride in his truck and he said that something was wrong, so now they are whinning real loud especially when on the gas compared to when they didn't before and i have no clue what it could be, there is no way they are suppose to be that loud, with the windows rolled up and the radio turned on you can still hear them, it almost sounds like metal to metal but it has plenty of gear oil and additive so i wouldn't think thats the case, so what do you guys think the problem could be? also are you suppose to pack each bearing with grease like you would do a wheel bearing, because we had a guy that we know ask us if we did and i didn't think we had to in this case.

 

You dont pack the bearings with grease.

What did you replace other than the ring and pinion of course?

How much backlash?

 

take the cover off and make sure everythings right and nothing came loose

 

I had to do mine like 8 times before I liked it. still whines a little but not much.

 

you dont pack the bearings, you want 6-10 thousands on the back lash. if you have a aluminum driveshaft that'll make them louder, anything other that a oem gear set is gonna be louder

 

my gears are actually quiet! so not all gears, but I would have to say 9/10 times they are

 

Sounds like a pinion bearing gone south.

 

you would be right, pinion bearing shot!

 

I have also heard that sometimes richmond wine. i did richmond 4.10's and had no problems tho.

 

back lash, I done some yukon 4.10's and set them up per their instructions and their spec was 3-5 and they sounded like a jet taking off. we brought it back in and set them to 8 and the noise went away.