Any Zero-Turn Mower Experts?

CRUZE 418 said
I don't know the answer to your question.
Do you have a copy of the service manual?
Why did the previous owner say that the drive units had been gone through? They have time limits on oil service and filter change. It's critical that all air be purged after oil & filter change, or damage to drive units will occur. That may be your problem. I have a TMX 6000 Toro ZTR. Toro owns eXmark. Our mowers are very similar. I changed my drive oil&filter at the first interval of 50 hrs, followed the procedure and have had no issues. My next interval is 400 hrs. My first guess is that something has happened to the left drive.
They are available on the internet.
Good luck!

Unfortunately I don't have a service manual. No idea. My dad purchased it and the guy claimed an older man owned it, always serviced it and just replaced the pumps and motors. Of course no paperwork. That's all the history I have, and it's shady at best. The odd thing is it doesn't make noise and there is no metal in the oil. Those are the two big signs of a pump/motor failure. My thought are to replace the pump as well as the motor, flush the lines and change the fluid/filter. Right side is still strong and has no issues.