A friend of mine stopped by and took me for a ride to listen to a noise his 95 Runner is making. He has an Automatic transmission and it is making an unusual whinning or howling noise around 4000-5000 RPM.
I checked his transmission fluid level and it wasn't low and the fluid smelled a bit burnt but did not look bad.
It just doesn't sound normal to me. Any ideas of what could be causing this. He has 96,000 miles on the vehicle.

 

I had the same noises with my 1992 4Runner, but it turned out to be the bearings in the rear differential. I eventually had the rear diff rebuilt.

Another idea is the u-joints. Maybe the u-joints on his truck are going bad?

-mangoango

 

The noise sounds like it's coming from something in the front part of the Runner but it could very well be the differential. I told him to have the Dealer check it out but he has a severe case of Dealer Phobia :pat:

 

I say check the fluid levels in the differentials. Also look around on the underside to see if he is losing gear oil anywhere. Those whinning noises are often something (bearing, gears teeth, etc.) running without enough lube.