[papaglide]

Originally Posted by rfrank

As it was explained to me and Ill do my best to explain it so bear with me. Cub hydro should be driven at recommended rpm to keep pump pressure constant there is some so to speak slip or slowing down of the hydro under a load. The engine is spinning a pump which in turn is turning a fluid motor. In our cars the fluid coupling is usually a torque converter. When incurring a load it gets to a point the pressure change causes a downshift to a lower gear driven by fluid in our cars. The cub hydro doesnt have gears to kick down too. The cub has a swash plate that tilts 15 degrees one way and 7 the other way. So for us to get constant speed there comes a point that you have to give it more angle to allow more fluid to be delivered to the hydro motor increasing torque. The springs and cam plate do a good job, but are limited to laws of physics. Other hydros use other means to try and offset the load. The sun hydro is a simple design, effective, maybe not terribly efficient but anytime you transfer energy thru another medium you loose energy. The tractor shouldnt come to a complete stop on most grades, Thats either out of adjustment or the pump is sufficiently worn that it cant apply enough force to turn the hydro motor.

Heres a good example. Spray a stream of water at a fan blade, it turns fairly easy, now spray that same water stream at the same fan with a head wind slowing the fan down(load), what do you do, either you spray the water towards the outside of the fan which applies more torque, or you increase the stream of water. Thats what we have to do with our hydros. Now if the wind picks up you get to a point where no matter how much water you spray it cant overcome the load of the wind. so something has to give, slippage. I hope this helps.

THANKS!! You explained that so well that even a simple dude like myself could understand it!! I do appreciate your explanation!!