Greetings all ... I'm a total novice but having identical issue with my Rover Rancher Auto Drive
I noticed that my problem only happened going forwards ... when reversing uphill the mower will climb until the wheels lose traction (so belts must be ok?) .. have you tried this?
I have rebuilt the drive with new corks, bearings, sprocket and chain and was still the same !!! by a process of expensive elimination i have concluded that its the linkage mechanism (threaded rod thingy as described above)
I hazard a guess that your problem is due to linkage , glazing or oil on the cork, or possibly binding of the clutch plate on the drive shaft.
Try adjusting the linkage first (like I should have) and if you have to take it apart swap the clutch and drive plates around upon re-assembly .. they are identical on my mower ...
good luck!
