Squeak when backing up?

[Capppelle]

OK I know I am new to the forum but any help would be great.

I have a 2001 Toyota Tundra, I have noticed a spueak when backing up but not sure what it could be. Then today i was backing up and a grinding sound started and when i drove back into my garage it took a little more gas to make the truck move forward well turning but seemed to move normal if the front wheels are straight.

Anyway i have no idea what it good be i have heard maybe a U-joint, but this is my first truck and i am not very good at this kind of thing....

any idea or if u have questions that would help u figure out whats wrong i'll do my best to explain it better...

Thanks for anyhelp

[Capppelle]

Ok, so I have a bit of a update. I was out to see if I could figure out where the sound was coming from. I got my wife to drive the truck back and forth well i was standing outside. So where the sound seems to be coming from it the rear differential. it seems to squeak only when backing up. If i put it in 4x4 it does the same thing but if i turn the wheel all the way it doesn't want to move i hope they are the same problem. It will move but it take a lot more gas to make it move.