The procedures are in the service manual. Basically jack up the rear of tractor until rear wheels are off the ground. Support tractor, start the motor, & operate the hydro transmission in both high & low. Operate it in both forward & reverse several times then raise the hydraulic lift up & down. Repeat a few times, then check fluid level, the first 2 time I did this cycle of operation I had to add fluid. Repeat this until fluid levels remain full.