[Bob Driver]

So the drive turned out to be almost out of fluid I took it off drained it cleaned it refilled it and bled it out and it’s working well at the moment. Fingers crossed it keeps running well. The entire drive was caked with dried up wet grass and oil that must have burped out of it from the heat. We cleaned it up and put the recommended 5w-50 (I think) synthetic oil in it. So far so good.
Going to do the bearing in the front wheels upgrade since the dang ole clip popped off and the wheel fell off. If it turns out to be a slick and long lasting mod eventually the other mower will get the same mod.

Yep.... Heat is the #1 killer of transaxles. Those little cooling fans on top are always undersized and if you let mowing debris build up, clocks ticking on a failure. Both Hydrogear and Tuff Torq advise against pressure washing their units, so your alternative is compressed air

 

[Bob Driver]

Most Tuff Torq axles have a recommended oil change interval of after the 1st 50 hours of operation and every 200 hours. There's also a filter inside the transaxle that you have to split the case to access..... They're not really keen to tell owners that little tidbit of information..... Here's a You Tube video on servicing the oil on a typical K46 in a John Deere. 12:51 in the video shows you the internal filter. Notice how dark the filter looks from the heat of the oil and manufacturing debris shedding. I've split them and found that little filter so plugged up it had collapsed. Tuff Torq is proud as hell of that tiny filter also, it usually runs around $25 from a Tuff Torque Dealer, but if you shop around E-bay you can find OEM for $10-$12

Tuff Torq Filter #TUF-1A646088211