Truck Repair: noisy differential, limited slip differential, axle bearings

Question
I have a  97 gm sierra 4x4 limited slip differential
its noisy at speed 65 to 110 km per hour . What is the
problem  , how much to repair .?

Answer
First, make sure one tire isn't significantly newer than the other, and that the tire pressure is correct.

Then, if the problem wasn't due to that, check the fluid in the diff, and see if it looks like a milkshake, which can be from water in the oil.

Axle bearings are another possibility.

Normally, if it is gear problems, it will be present at all speeds.

Another thing to check is the u joints, and make sure the driveshaft isn't bent.

Van