Last night a buddy and I swapped in a gxl lsd with mmr solid mounts. We bolted it up, filled with Lucas 80w90 gear oil for lsd's, and took it for a drive...

it makes a whining/humming noise all the time. whether on acceleration or cruise or deceleration. It's definitely not a wheel bearing, we put it back in the air to check that. The noise seems to be coming from the diff itself

So could i just have bought a bad diff? Incorrect contact between pinion and ring gear maybe? Backlash doesn't seem too tight or too loose....

 

Solid mounts will transfer more noise into the car, it's about as likely that is all you are experiencing as it is that there's actually a problem.

 

well i just went and abused the hell out of it :P lol... clutch kicks, burnouts, drifting... and it seems to hold up ok.

 

clutch kicks will be harder on your trans, the rest.... eh pends on how much power and how often you do it if it will cause problems. check ur diff for leaks. pray it isnt grinding

 

it does this on my stock diff...

 

you put on Solid Mounts..the sound of the diff is going to be transferred into the Cabin..I Have solid Trans and Engine mounts,and it sounds Pretty "scarey"..heh,heh..like it is Gonna Explode due to Power!