Block the machine up so all four tires are off the ground. Raise and latch the seat up. Once the seat is up you will see a yellow plate with a bolt and spring attaching it to the rear of the engine bell housing. On this plate you will see two sets of 1/2" bolts, it takes a 3/4" wrench. The bolts attach two blocks to the underside of the yellow plate. The blocks are supposed to be in contact with the two rollers on each arm which comes out of the hydro pumps.
Place the service run switch in the service position and start the engine and release the parking brake. Loosen the bolts on the blocks and slide them away from the arms. The pumps should center themselves and the creeping should stop. Once the creeping stops move the blocks back up to the rollers on the arms. The blocks must contract both rollers on each arm or you will continue have creeping problems. It may take several attempts at moving the blocks to get the creeping to stop.
You should also look at the front of the yellow plate. You should see four small screws. Theses screws attach two plastic guide block to the plate. If these screws get loose or lost it can cause some creeping problems and if the plastic blocks come off you will have control problems.
Do not attempt to stop the creeping with the skid loader wheels on the ground!