I was wondering if anyone has seen or heard of anything like this?? On my friends 97' 4X4 Taco...when you are cruising about 30 mph and downshift to slow down there is a weird grinding sound coming from the rear. It sounds almost like the rear brakes grinding, however it does it even without applying the breaks. So far we have pulled the rear brakes apart and everything looks fine, shoes have plenty of meat no leaking wheel cylinders. He inspected the drive shaft and u-joints, and also changed the rear diff fluid and everything looks fine. The weird part is that it only does it when down shifting from a high speed...not when you hit the breaks. Any ideas would be appreciated. Thanks

 

Is it when the clutch is slipping? If so, it might be the clutch. It might also be some sort of vibration caused by a loose mount.

 

don't downshift! it's bad for the transmission...

 

Downshifting at higher speeds wears the syncros. If you downshift like that, you should double clutch. Do not confuse it with speed shifting.