If you have flipped the lower handle, that is about all can be done w/ the existing handles. If your local mower shop stocks a few handles or you see shorter ones on a Troy, Yardman, Yard Machine, White or Cub Cadet mower- look a bit closer as they may interchange.

Look at the obvious things first. Are you able to turn the engine via the top screen by hand? If so, next check the fuse. You may have to pull the battery to get at the fuse holder or it will be behind the dash, or under shifter plate(depending on model). Then check the solenoid. It will be the relay at the end of your positive battery terminal. If you can jump power to the small spade terminal on the solenoid and it the turns, you have an imput problem. Likely input problems are ignition and safety switches and what actuates the safety switches. If it doesn't turn, then jump the two big terminals on the solenoid. If it turns, you have a solenoid problem. If not jump directly to the starter and if it doesn't turn and the engine is free, you have a starter problem. I would be concerned that there is something drawing current from the battery or that you have ac output directly to the battery. Have a multimeter?

I bought a troy built pony in 2015 15.5 hp, when blades were engaged the mower vibrated a lot. I eventually found out that this model shakes, vibrates when blades were engaged, as I went back to store and started a brand new mower, same as mine, they engaged the blades and the mower shook, vibrated like mine. I found a simple solution to the problem that works for me. Instead of pushing the blades engaging lever the whole way forward I push it just to where blades are just engaged and put a 14 by 1.5 by 3/8 piece of wood between the seat spring and the deck cutting heighth lever to hold the blade engaging lever. believe it or not the mower does not shake or vibrate. belts are not hot after I am done cutting my grass

1- A little searching on the web should find a new breather tube. If not, definitely plug the hole in the housing. 2- The engine mount should slide on the rods and the bolts w/ jam nuts are to hold the rods solid in the tranny housing. The bolts are not fill holes. The plastic caps are removable so you can screw a short bolt in them to drive the pin out of tranny housing. It sounds like the engine mount ears are seized on the rods. Some Kroil, PB blaster, etc and patience should free them up. 3- I'll suggest replacing both wheel axle seals and tine shaft seals. If this is a PTO model there are two points to check oil level in the tranny and tine gear boxes. You can go to the troybilt site and download an owners manual. Until the seals are replaced be sure it has plenty of oil. If not it will get expensive to repair. You have a good rugged machine. If properly repaired and maintained it will outlast you. Mike