580ck dont move until warm ???

I bought this 580ck in the spring and it didnt move at all. I tore it down and found a busted keyway for the shuttle pump fixed that and it moves now and has worked all summer but i have kinda questioned if the clutches are slipping or not now that its getting cold outside it dont move until it gets good and warm. After it warms up it does move but its almost like its slipping (same as it has done all summer) it always shows in the green on the clutch pressure guage even when cold. I have...

580ck dont move until warm ???

580ck dont move until warm ???