2001 Chevy Silverado loud squeel coming from the back?

[TDP]

It's most noticable during low speed. It seems to come from the center of the truck towards the back of the vehicle, not from the engine. It may be the u-joint, if so how much would that cost to repair?
It only does it when accelerating, and the squeel gets faster as you go faster.

 

[countrylovin]

u joints usually make a banging sound, not a squeal. Take it to an oil change place and have them check the fluid levels in the differential.