Vibration or droning at 75mph with throttle ON
 

When cruising at 75mph, depressing the throttle causes a sort of vibration or droning. Low frequency, constant.

I went to 2WD and it still happens, so it is not the drive shaft, rear axles, or rear wheel bearings. I pulled the two front axles and sent them to a specialist to be checked - nothing wrong.

All mounts are okay - the rear tranny mount is new.

This is frustrating! What else could it be?

Could be a lot of things, muffler hangers, etc. Could also be differential bearings. Tough to tell without being there.

Beav

Not muffler hangars - I checked the integrity of the exhaust system. Diff bearings...? Maybe.

Is there a diagnostic procedure?

Yes and no. It can be difficult sometimes for even an experienced ear. Best bet would be a free inspection at a recommended tranny shop.

Beav