Massey Ferguson 1635 hydraulic problem

[Baileebrett2]

Seems to be a hydraulic problem on my 1643 MF…….When I put the tractor under load either pulling a slight hill bush hogging or pulling another implement in the field the tractor stops moving forward. I can shift into snail range (1st gear) and the tractor will move slowly. I have a power shuttle

 

[Harry in Ky]

Seems there are a few different transmission options for that model, but the parts list doesn't show any drive plates other than a single dry clutch option to power the transmission input on any of them. Are you sure you don't have a dry clutch ahead of the power shuttle and the that clutch isn't slipping and causing your issue?