Mustang XP left side fails after going up steep hill

Hi all,

I have a Troy-Bilt Mustang XP zero turn Model# 17BF2ACP011

I have a steep hill in my yard and the mower has been fine cutting it at an angle. Last week while cutting it lost all power to the left side and caused me to turn left and drive down the hill. Once back on flat land it seemed like I could slowly get the left side working again by pumping the handle. Currently it works fine on flat land but anytime I get the mower at an angle the left side dies.

Any thoughts on what to try? It has a hydrogear ZC-ambb-4ddc-2rpx on the left side if that matters.

Does that model have separate drive belts for the left and right drive, and if so check the condition of the belt. If one drive belt for both drives there may be other things going on with that drive.

I fixed it!

I removed the hex head oil fill plug on the left hydro-gear (very tight!). I used a cut solo cup and pored 10 small cups of 20-50w oil in the refill hole. went and worked it back and forth a while on flat land. Now it runs up the hill fine, just low on fluid!