Chattering wheels at full steering lock

[chelli]

Hey guys, just recently got my transmission fixed and replaced with a used outback transmission. But, some reason, when i am doing a tight turn... lets say, u-turn or hard 90 degree turn, the back wheels try to lock up? and what i get is like chattering or the rear wheels keep getting locked intermittenly, causing the car to skip a little. I guess it stems from the same prob, but when i am trying to come out, or go into a parallel parking lot, i need to gas it a lot to move... does not roll forward/backward when i release the brake. Any ideas?

Ben