Hydro Drive slipping

[NateCliffJump]

Hello all, first post here on the forums.
I have a Toro Timecutter HD MyRide 54" (75212), around 3 years old, 70-90 hours. This uses the Hydro-Gear ZT-3100 hydro pump/drive.
The drives seem to be slipping whenever I move forward or turn. They will slip momentarily, and then catch up and turn the wheels.
From what I've read, I'll need to check the belt to see if it is loose or damaged. Are there any other items to check before considering something like hydro drive oil change?

I was looking through the Toro manual for the mower, and it does not mention anything about the drive system maintenance. However, when looking in the hydro drive manual, it definitely call for maintenance.
I haven't seen any reservoir for oil for the hydro drive, and the Toro parts list does not show a reservoir. Is this serviceable or is it intended to be 'sealed' with no maintenance?
Links below for reference.

Thanks!
Nate

Mower Manual:
https://www.toro.com/getpub/160697

Toro Drive Assembly Parts List (scroll to Hydro Transaxle Drive and Rear Wheel Assembly )
https://www.toro.com/en/parts/partdetails/?id=49144

HydroPump Manual
https://www.hydro-gear.com/6a7ea2cd02_sites/hydro-gear.com/files/BLN-52441_P19.pdf

 

[keakar]

they need fluid to live, run low on fluid and you burn up the hydrolic pump thingy inside and its DOA

watch this video that shows you what you may be in for