Rear End Noise 8 3/4

I have a 70 Dart Swinger with a 8 3/4 rear end. When I press on the gas pedal I can hear a whinning noise from the rear end... It stops when I let off the gas and starts again when gas is given.

I have been told I need to "set up" the rear end to stop this noise of whinning/whinding.

What is required to "set up" the rear?? Is it a complicated process? Special tools required? etc. etc.....

Any suggestions?

Thanks

Jeff