Ok guys I seriously need help with my truck. Lately I have been hearing a high pitched noise from the rear of my truck when moving at speeds above 35+ mph. Its a very distinctive noise and I seriously feel like a dog because it drives me nuts.

Does anyone have any clue on what it could be? A search turned up a not so clear answer.

Thanks in advance

 

Might check the u-joint and pinion flange on the rear driveshaft.

 

does it make the noise all the time, or when only accelerating or only when decelerating?

by high pitched, do you mean like a sqealing, creaking or whining?
if it's a squealing, it may be something in the brake system, but usually that's a disc brake type noise.
if it's creaking, like door hinges sound sometimes, the u-joints may be dry and needing greased or replaced.
if it's a whining, or maybe even a high pitched howl, the pinion bearings may be loose or you may need to drain and refil the differential.

 

Thanks for the response guys.

The noise is on acceleration and deceleration, and goes away when I finally reach a stop.

The squealing is very high pitched. The diff fluid was changed like 1k miles ago although it was filled with a mix of 1qt 80w and 1 qt75w-90 gear oil (don't ask long story)

I'll replace the diff fluid again today with the correct blend of full 75w-90 and replace the ATF again.

 

definitely check your u-joints. if the bearings in the joints are dry, metal on metal, they can squeal quite loud and high-pitched.