2000 2500 quad 4X4 140K all stock and I bought it new. Noticed a couple of weeks ago when i shifted the transfer case from 4h to 2h it was taking a long time for the 4X4 light to go off. The other day it quit shifting from 2nd to 3rd unless I back off the pedal then it shifts. If I get back on the pedal too fast it starts slipping. All other shift transitions are fine and it does down shift into second with no problem. Any ideas?