hi guys I 'm looking to buy a 1989 gmc 1500 4x4 converted to a 6.2l 86 diesel.why? dirty cheap snow plow truck.my fear is the transmission is the original v8 gaz automatic(over-drive)transmission is still on it.did the gas and diesel transmission the same?is the original trans can take it? should I rebuild it or change it? I search all day long on google and can't find nothing on it.hope you guys can help me.