HST Problems - need help

[pittpeng]

I have a g5200h, 15hp diesel lawn tractor. She's run like a champ for a few years, but suddenly she decided to not want to move any longer. The engine is fine and the drive to the HST is spinning properly. But when you put the pedal into forward or reverse she will barely crawl and with little to no power. All fluids and filters have been changed at regualr intervals and recently. Just took apart the entire HST (took a day), and there's no swath, no scaring, or any damage of any type internally, I was amazed at what good condition she was in. I've heard of these old smaller HST's going bad from heat abuse as they age, but no specifics. Anyone run into a similar problem and know the fix? I'm guessing its the hydraulic pump, but I'm not sure what the pressure should be anyways and I don't have a pressure gauge to test it.

[Service Dept Vic]

Let me mull that one over this weekend. I'll report back with an idea.

[pittpeng]

Thanks. I'm looking foward to anyone with some advice. Do I need just a new hydrostatic pump or do I need to replace the entire rear? When I spin both wheels, the gears going to the hydrostatic pump are turning. I guess I need to pressure test the system. Anyone know what the pressure should be?

[Service Dept Vic]

Pressure testing would be a good place to start. You'll need a WSM to follow all the flow testing on that transmission. I don't have a spec for that little unit or I'd share it with you, but there are several checks with that guage that are done to determine where in the HST system the problem exists. The diagnostic trouble shooting chart is very long and detailed on that transmission.