Finally got 4.10's to run quiet in a 10 bolt.

[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.

[Whiplash Performance]

That sounds like how it normally has to be done.
With some resistance to spin the pinion is how you setup a brand new set of gears. I set up mine using an impact on the pinion nut using the torque to spin the pinion to determine how tight I should make it.
I did my 3.91s in the rear in my goat with all the proper tools and it doesn't whine even up to 170 mph.

[Little G]

I had 4.10s in an auburn posi pro and they were whisper quiet up to 100 at least

g

[alamantia]

I didnt have an adaptor for my in/lbs wrench so I did it by feel but it felt too tight. I hope the bearings break in before they burn out. I guess only time will tell

[r0nin89]

Yeah your NEVER suppose to torque the pinion nut with an impact gun, ever. Sorry not to be a dick but I dont care how many people say you can do it or how many old school mechanics say its fine. Your suppose to use a cheater bar and set it to assembled rolling resistance with an inch pound old school torque wrench.

If its too tight you'll probably chew the bearings up quicker than you normally would.

And did you ever think that perhaps your other housing is tweaked/bent and causing the noise in the gears? Or maybe its an outer bearing?

[alamantia]

I think its ok to use an impact gun. All the force that the pinion nut generates is applied onto the yoke which is then applied to the portion of the bearing that the rollers reside in which is applied to the crush collar. While you are torquing down the nut the actual rollers themselves are still floating around with no force on them until the crush coller deforms enough that the rollers kiss the races. Its once they touch the races that you get your preload. That being said. As long as you dont over torque with an impact mashing the rollers into the races you can pound away as the collar deforms. Trust me, I tried with breaker bars, but I couldnt get a good enough grip on the yoke to budge the collar.

As for the other houseing, I guess its possible. But its definitely gear noise. I dont think an axle being out of parallel would effect the center section. I think having an aluminum driveshaft radiates the resonance given off by a loose pinion. All i know was that it was god damn anoying on the highway and im thankful its gone for now.

[r0nin89]

Originally Posted by alamantia

I think its ok to use an impact gun. All the force that the pinion nut generates is applied onto the yoke which is then applied to the portion of the bearing that the rollers reside in which is applied to the crush collar. While you are torquing down the nut the actual rollers themselves are still floating around with no force on them until the crush coller deforms enough that the rollers kiss the races. Its once they touch the races that you get your preload. That being said. As long as you dont over torque with an impact mashing the rollers into the races you can pound away as the collar deforms. Trust me, I tried with breaker bars, but I couldnt get a good enough grip on the yoke to budge the collar.

As for the other houseing, I guess its possible. But its definitely gear noise. I dont think an axle being out of parallel would effect the center section. I think having an aluminum driveshaft radiates the resonance given off by a loose pinion. All i know was that it was god damn anoying on the highway and im thankful its gone for now.

Trust me its not ok to use an impact gun. The reason being is that MOST times you'll crush it too far and then the tension drops off cause the crush collar gives out. I actually made up a rig for holding the yoke through the strap holes with a 3 foot bar on it and a 2in hole in the center for the socket to go to the pinion nut.

Its definitely a 2 person thing or a bench thats actually sturdy and bolted to something concrete with a jig on it.

[alamantia]

Yeah, i was doing it on my work bench and didnt have a monkey wrench at my disposal.