2000 Wrangler rear end squeak

My 2000 Jeep Wrangler with 81,000 miles has recently started making a squeaking, almost rubber on rubber like sound when turning and accelerating at low speed, seems to be coming from the rear differential.
I recently rotated my tires and checked PSI in the hope that it would help, no change. Any tips?

Have you taken a look at the rubber bushings for the shocks and the locating bars for the rear axle? That's the first place I'd look.