Transmission or rear end or other?

1996 4Runner V6 4WD with automatic transmission & 136K miles. I believe it has a limited slip rear end. Problem only occurs in drive, not in reverse. Put in drive & put on the gas & sometimes engine increases RPMs (1000) & it feels like it is trying to move but won’t (as if the brake were on). Then a “clunk” is heard & felt in rear & car drives normally. Only occur when starting from a stop. A few times on snow or ice one rear tire will spin & the other feels like it is dragging (not rotating). Passenger rear wheel bearing replaced about 1 year ago. Transmission fluid is fine & changed about 1 year ago. Thank you for your help.