I've got a Wheelhorse D200 that I'd like to do some work on this spring.

The hydro transmission is strong in reverse. But, it barely has any power in forward.

The previous owner messed around with the linkages, so I think they are tight, although I'm not too keen on his work. So, I'm thinking it is time to clean the transmission & replace the seals.

However, how can I be sure the problem is in the pump vs the transaxle?