Actually, I had the local Bobcat dealer fix it. Mainly because I'd just bought it, and it was making the hyd. system do funky things. Air was entering the system, by syphoning back through the motor's when shut off, foaming up the oil.
I pestered the service manager for a couple days, and did all the checks he recommended. Finally threw up my hands, and took it to them. They did all kinds of diagnostics, and really could not figure it out either. It finally took a conference call of their 4 other satellite stores, to service managers, and one had the answer.
Actual parts at the time, less then $50.00. Labor, $900.00. Naturally, it had to be gutted to get to them...
That was 6 years ago, and it's still doing fine..!!