I have a troybilt tiller just given to me from my uncle. The only numbers that i have to go on to ID the tiller are on the transmission casing.They are 20512ct and 20508CT (BF). I need the owners and service manual. The tines will cease to turn once the tiller is cranked and shifted into the forward gear and the tines make contact with the ground.I am thinking that the belts need tightening. I would appreciate any help that you could give.