Maybe someone could help me. I just bought an old boat with a 1966 johnson model VXL-12R. The motor runs great-but grinds when shifted into foward. Reverse works with no problems. I have no experience with lower units so i'm not sure whats going on. With the engine off it all seems to shift fine, but when running, foward just grinds. Any imput would be great. I have taken the prop off and what gears i can see look fine. There is proper oil and no visual leaks. All the shift linkage appears fine and all bolts are tight. Is this a problem that can be fixed without removing the lower unit? Hopefully somebody can give me advice...