Hello I have a 15.5 hp mastercraft lawn tractor I just took it out of storage run it awhile and started to drive (after fresh gas etc) it has a hydrostatic transmission it worked fine for 10 minutes then started to labor hard as I push forward or reverse on the speed stick it forces back on it (now will not move in any direction) ichecked the neutral selector etc no luck any one experience this before?

hello i have a 15.5 hp mastercraft lawn tractor i just took it out of storage run it awhile and started to drive (after fresh gas etc) it has a hydrostatic transmission it worked fine for 10 minutes then started to labor hard as i push forward or reverse on the speed stick it forces back on it (now will not move in any direction) ichecked the neutral selector etc no luck any one experience this before?
I have the same tractor, and had the same problem 2 years ago. I topped-up the gear oil in the rear end (pull the console plate off by removing the knobs for the brake and transmission lock and two screws -- you'll see a rubber line tucked under the l/h side with a red plug in the end -- I believe that's your fill point, at least, it's where I filled from.).

But... I don't know what oil the manufacturer recommends. I used farm hydraulic oil, and I'm thinking it might be too heavy -- I had a bad leak out of one of the rear wheel axles and lost all my oil several times. Now mine is acting up again and often not engaging the gears at all. So I'm kind of back to where you are now, only worse.

It's a possibility I've done some gear damage by running it dry. Or maybe it's because the oil I added wasn't to spec. I really don't know. Topping-up did fix it for a couple of seasons, and I've been cutting 5+ acres with it. But I do hope what I've shared with you helps, at least a little.

And if anyone has more information available to help us both out, that would be good also.