[alamantia]

My car came stock from the factory with a torsen posi and 3.42 gears. About 5 years ago I bought brand new motive 4.10's and an install kit and paid an installer to preform the swap. They ran quiet up intil about 60mph and would whine from 60mph on up. Quite annoying. I tried different types of lube but none seemed to make a difference.

After about a year of this I figured they were set up incorrectly and bought another brand new set of motive 4.10's and an install kit and brought it to a different installer and paid for a swap. This second set of Motive 4.10's ran dead quiet up until about 60mph and then whined from 60mph on up. No difference from the first set of 4.10's

Another year went by and I read up to find that AAM gears are to be the quietest. I bought a brand new set of AAM 4.10's and an install kit and brought it to a 3rd installer and paid for a swap. They ran dead quiet up until about 60mph and whinned abouve 60mph.

Oh well, I guess its meant to be right? For the last few years I have accepted that 4.10 gears in a 7.5" 10 bolt will whine over 60mph.

I had picked up a rear out of a wrecked 95 Z28 with an Auburn posi and 3.42's. I figured I would keep it as a spare rear in case I ever hurt the one that was in the car I would have a back up. I got bored a few weekends ago so I dissasembled it, sanded it painted it and decided to install one of my old sets of motive 4.10's that I had laying around that whined figuring that I would have two 4.10 rears, one in the car and one out of the car. The only thing is I didnt have any spare shims or set up tools. I just torqued down the pinion nut with an impact until it was tough to turn the yoke and pounded the posi in with a dead blow usinng the shims that came in it with the 3.42 gears. I checked the pattern with some lithium grease and I was surprised to see the pattern appeard good. I didnt have a dial indicator so I couldnt check backlash so I dont know what its at. I assembled the rear, filled it with lube and decided to swap the axles over the weekend. The one thing I did notice is that the rear I set up is much harder to spin the yoke than the rear I removed from the car. Perhaps too much preload on the pinion nut? Im not sure because I dont own an in/lbs torque wrench. Anyway, I took the car for a ride and cant get it to whine at any speed, I drove it all the way up to 80mph and it wont make a peep.

I find it hard to believe that with 3 different installers, 3 different sets of brand new quality gears they all whined. I perform some back yard mechanic, slap together job and its dead silent. Perhaps overtightening the pinion preload keeps it quiet?

Kinda wierd if you ask me.