Right now the only steering mods I'm doing is freeze the pivot on the axle, reason being when I was driving it and turning around the outside front corner would dip and the rear inside corner would lift up. Speed I'm shooting for is somewhere between 20 and 30 mph.
Something else to add if you're cleaning out a mower transaxle trying to get all that bentonite grease out its a three phase process, phase one scoop as much of the stuff as possible out with your hands (wear gloves!) Then using Brillo, SOS, etc type pads (steel wool and soap) remove most of the grease from the inside of the Trans case, sides of gears, shafts, ect.
Phase two get a pot or a metal basin (metal basins are cheap) and fill with water and add two cups of laundry detergent and two cups of dish soap, (I used Persil and Palmolive I would've preferred Dawn but use what ya got) then put all the parts including the case halves in the water, bring the whole thing to a boil and keep it there for at least 4 hours do this twice, now getting it up to a boil takes forever so do it on a weekend when you are completely free, now I used cinder blocks to make a makeshift stove which worked pretty well my only advice if you go this route leave two side open for air it make the fire much hotter hot enough to make any metal that's in the fire glow and make the bricks glow too, another thing the bricks will probably be toast afterwards because the heat makes them disintegrate, my stove that I got the most heat with was built with 20 half height cinder blocks with the smaller narrow holes on the sides, use 6 to make the base, 2 long 3 wide, then at each end center two blocks with the holes horizontal and place a third block at each end atop the two you just placed with its holes vertical, then use four more on each side with their holes vertical to make the sidewalls, what you'll get is a rectangular stove with a ledge at each end and a square pit in the middle, I used smashed up pallets as fuel because they're free and have a good bit of wood, try to find ones that are made of oak or something like that and a few pine ones too, now build a fire with the wood on the two ledges, have plenty of fuel ready, start a free going then have a friend help you set the pot of water, parts, soap, and detergent on the stove, boil for the time I mentioned, expect to use at least four pallets each time, once cooled remove the parts and drain the water.
Phase three now with the parts boiled twice head to a local do it yourself car wash with the parts and basin in hand, use the high pressure soap to remove the remaining grease, some parts like washers and bushings will need to be cleaned by hand with aforementioned Brillo pads, but do the case halves, shafts, and focus on the gears the teeth hold onto the grease, wear old clothes and possibly some safety glasses/goggles, do not use just water use the soap setting because the water alone will not remove the grease, well that's it for my tips on cleaning mower transaxles.
I've got a Deere S82 rear rider, bare bones but with a Peerless trans still mounted. At one time I was thinking about reviving it to a yard work cruiser.