New Holland L425 does not go straight with both handles pushed forward

Just purchased and the seller said the thought it was a hydraulic leak, but from the service manual it appears to be an adjustment issue. Reverse is fine, but you really have to ride the right handle to go straight forward. Service manual says Steering lever stop bolt not adjusted correctly or Transmission control linkage loose on pintle shaft. It refers to operators manual to adjust but I don't have that. I does have some leaking fluid, but before I go changing hoses I wanted to see if there might be another solution.