Small Engine Troubleshooting Problems? Ask a Mechanic Now.
The hydrostatic transmission is not supplying the pressure for the drive and steering. It requires testing of the pressures of the unit. And it pressures are low in the main unit, rebuild is necessary. Here is service manual link that starts the Hydrostat at page 775. It shows the test port for the charging pump, which is the first test that need to be made. It may be something that you would need to take to dealer to have tested and repaired. Here is direct link to manual below.