I have a L1-38 with the 4 speed PTO. I want to run a rough cut mower that operates at 540 rpm. The question is what gear is the 540 PTO rpm on the tach set for and what are the gear ratios of the 4 gears. My concern is that the tach indicates I need 2700 engine rpm to get 540. That's pretty high and I find the tractor has plenty of power at 1500 - 1700 rpm. I bought the L3750 manual but it is only for the 2 speed PTO. Thanks for the help.