Have a M135GX 4 wheel drive I bought new in 2012 and now has about 3500 hours. Went to move it earlier this year after it was parked last fall after planting and noticed the brakes seem to be sticking. You can move the tractor but it stops by itself when you depress the clutch, even going down hill. Removed parking brake thinking it was stuck but it was fine. Released pressure by opening the bleeders on back axles and also took brake lines loose. Still no luck. Only work other than regular maintenance has been the transmission was rebuilt a couple of years ago by the dealer. Any help/suggestions greatly appreciated.