My old Metro is wearing out. I am the second owner of the fabulous cutting machine. The old Command 13 is smoking bad and the transmission is slipping. What engine is recommended as a replacement? I also have never serviced the transmission, not knowing what lubricant to use, and is there a rebuild kit for the transmission available should I need one if adding fresh lubricant doesn't solve the slippage issue? This machine cuts and mulches beautifully and I hate to put it out of service.