Just bought a 1995 1/2 Tacoma 4x4 auto trans and while driving it I noticed a wining noise that comes on at 25mph under load only. If I let off the gas the noise goes away. I was under the truck and it seems to be coming from the drive shaft not the ujoints but the slip or expansion section not sure what you call this part of drive shaft. The drive shaft at the rear of trans has a center bearing ( it seems good) then this unit. I ran the truck while I was under it and the noise seems to come from were one shaft slide inside the other I greased all fittings including the one on the yoke of the slip joint but no change?

 

No, they're usually in the front. Maybe it's the kids haha.

Well, check your diff fluid, driveline and brakes for starters.

 

I checked diff and changed fluid no help and rear breaks were replaced to pass state inspection. The only thing is, it makes the sound only when you accelerate when you let off the gas the noise goes away. The noise sounds a lot like tire noise tried different set and no effect still noise.