Excellent advice from Rockit.
Just to be sure... take a look at the rear axle cups and make sure both are fully seated in the trans. Meaning, ones not hanging out of the trans farther than the other.
Did you just replace the axcel or do more?In turf mode both wheels must be on the ground. Otherwise the diff will just put the power to the wheel with the least resistance. If in turf mode when shutting it off or turning it on do you hear the diff lock solenoid?