I didnt design mine with a transmission,just the hydraulic motor driving the transfer case..I went thru three motors looking for the right torque/speed ratio..still has plenty of torque to push and dig with, I mainly use it for moving small generators around and snow removal if we get enuf piled up here..The place I want to upgrade on this little machine is the pump, I had a 2-section ancient BorgWarner pump on it originally with just the right gpm for drive and lift/loader functions,it cracked+exploded when doing dirt work around here after about a month..it was too old to reference numbers or size,easier to use gear width/size to tell..so I found a new surplus dual pump on SurplusCenter for pennies($79) and its been working great ever since but needs more flow in the loader section,its OK but still a little slow..I think next time I work on it I'll order a brand new pump three section and custom spec it out so the flow rates are improved..only one pump mount is doable on this machine,no other way to practically mount and drive another pump except with a drive-thru pump(mounts one pump on the back of another)-got one as well havent doen anything with it due to other work right now..I think would add too much to the length of the pump sticking down under the machine as I have a vertical pump drive. Its always a work in progress but has stabilized now with little breakage..just a little slow FWIW
