on the car that i'm buying tomorrow, the guy put a 4.10 rearend in, and there is a wierd noise coming from it and he says it is a result of that. He said its a Richmond rearend. The noise is like a humming, sort of, or maybe like a howl..it isn't loud, its just there...i was just wondering if this was normal... And also, i am going to put new tranny fluid in and new oil in the rear end... Whats the best oil i can buy for each? Thanks.

 

If the whine isn't too loud then I would say it is normal. Only the best professionals can install gears perfectly with no whine. I had a shop install a set of Jegs 3.73 gears and they whine around 60-ish in sixth gear only.

The whine is caused by a slight missalignment which is very hard to correct unless like I said a pro does the work. However, changing the rearend oil may solve the problem or at the least make it better. Hope this helps.