noise from rear at high speed

Hello; this is my first post.

While cruising on the highway, the limited slip will make a clunking, chattering noise when I press hard on the accelerator. At about 90mph and above I can hear this. It makes the same noise around corners at high speeds, but I dont see why it would make that noise when accelerating straight at high speeds.

This might be related; my car used to spin the tires from 1-2 shift with ease, often without even trying but now I have to stomp the gas to make the wheels spin and it most often it doesnt spin.

The car is automatic with 3.73 motive gears, and the stock lsd was replaced with an Auburn.

I changed the gear lube last year with 75/90 synthetic. Is something wrong with the rear? Was it a bad install?