ever since i installed a motive gear 4.10, eaton posi, and energy suspension poly bushings i have this problem not to sure which one is the culprit though
when i get up in speeds on the highway,dragway,whatever
my rear end area...makes a very load drowning noise...that is in a pulsing type of way.....youlet off of the trottle and is slows down grandually but it is horrible.
i pulled the small plate that goes above the energy suspension bushing and the noise/vibration went from around 70 mph to 80mph.
i replaced both u-joints
inspected rear end....no metal
added the posi additive
checked pinion angle due to lowered car with eibach sportline springs...seems ok
any ideas or similar problems? thanks for your help

 

sounds like tight lash in the ring and pinion.

 

Just my opinion, 4:10 gear ratio are not ideal cruising gear.

 

i agree with skirkland, check the lash in the gears and also agree with DJP prob. not a good cruising rear end

 

whats a good lash to have for my set-up? i agree also...but its one of those things you do...and realize after you installed them and drove it, that you should have installed something like 3.73. i have also heard that it could be the driveshaft...stock set-up spins at certain speed so when you change the gear ratio the driveshaft spins fast than it was setup to do and when you get up there in the rpms it would create more noise and the only way to fix the problem is to put in a bigger diameter driveshaft? what do you believe in this ?

 

well if it is a cruising car you should prob. swap to a 3.73 if that is feasible for you, if not you need to look up the gear lash if you have nothing previously marked, which i am assuming you do not if this is a new rear end for you, or you can just deal with the noise and most likely accelerated gear wear