A couple of weeks ago I noticed that one of bolts that attaches the right side of the transaxle to the frame of my 129 was loose, and had backed out quite a ways. I tightened it, and found the other bolt on the right side was loose as well. I looked at the left side of the transaxle, and the bolts were MISSING, and soon determined that they had snapped off at some time in the past, flush with the center part of the rear end. After tightening the loose bolts, I had to cut the grass, and noticed that the hydro speed control almost immediately worked better.
I figured having narrowly avoided disaster this time, I figured I better fix it properly sooner rather than later, so I went off to TSC for a #3 easy-out spiral screw extractor, along with a fresh 1/4" drill bit to try to extract the stub. Of course I had to pull the axle, which meant draining the transaxle, and proceeded to drill the hole through the stub of the old bolt. As you can guess, the extractor merely chewed up the remains of the old bolt, along with any of the original 3/8 thread. Once I had satisfied myself that the original threads were beyond salvage, I stopped after work for some more tools, this time a fresh 23/64 drill bit, a 7/16 tap, and the necessary grade 5 hardware I would need.
Its all back together, though I need to let the RTV cure overnight before pouring the Hy-Tran back into the transaxle. Here is what she looks like before I replaced the axle and wheel.