Z-Force LZ54 - Sudden Loss of Acceleration + Black Particulate

Hello everyone! Coming to you today with an issue that has me stumped. I am typically a garden tractor person, but borrowed my father's ZTR this week to get some mowing done. He mentioned to me that he's been having a sudden loss of power in the transmission on the driver's left side occasionally. I was able to replicate the problem a few times, but the issue is sporadic.


When going uphill, occasionally the transmission would slow on the left side. As the mower slows, pushing the controls further forward does not help. Easing off the controls about 3-5 inches then pushing forward again engages the transmission and the mower accelerates. There's no loss of engine power at any time. The slowness appears the be directly connected to the driver's left-side transmission.

I noticed a black particulate similar to brake pad dust on the outer housing of the mower deck on the left side. It is very fine, shows no sign of grease or stickiness, and it blew away clean with the force of a leaf blower. I am unsure if this is connected to the transmission issue, as this is not my mower, and I've read several posts about "mold season" and that black spores collecting on the deck can happen in the summer.

Any thoughts--photos attached!

https://www.cubcadetpartsnmore.com/cub-cadet-service-manuals

check deck belt for wear, may need to be replaced, left side transaxle needs to be looked at by certified technician.

A worn drive belt was the culprit here!