Make sure that the selector handle on the left of the seat for the PTO is locking into the correct position to give you the 540. If you go to the back left hand side of tractor and look at the PTO selector linkage, you will see an area where the linkage has what I believe to be a spring loaded ball that pops into 3 different positions. 1 position is 540, 1 is neutral, and 1 is ground drive PTO. Make sure you are getting locked in the correct position. Do not know if you know this or not, but when not using PTO, selector should always be run in the neutral position according to owners manual. HOPE THIS HELPS.