I am having some starter issues truck is an 85 F250 4x4 with a 351W bought it for 600 bucks had a parts truck exactly like it sitting at home. so I pulled the motor from the parts truck rebuilt it and put it in the new truck (both motors where fine as far as they ran and started no problem) now that i have the fresh motor in the truck the starter grinds when trying to start. i replaced the starter the solenoid and the battery and have had no luck does anyone have any ideas. its starting to frustrate me to the point of selling the truck which I don't want to do because of all the time and money put in to it

 

Were both trucks auto or manual? The starters are different for the two, with the starter for an auto trans having a longer throw.

If they are the same then it sounds like you have a flywheel/flex plate problem. Something is wrong with the teeth.

 

both trucks are c6

 

Does it grind every time you try to start? If so that is usually indicative of a starter problem, or the starter isn't going in correctly, or the flex plate is not down on the crank properly. A grinding problem every once in a while usually indicates a bad flex plate. But, a bad starter can tear up a flex plate and vice versa.

 

it started out as once and a wile now its every time

 

Then you probably have at least ruined the starter and probably the flex plate. If you have bad teeth on one they'll mess up the other. So, for instance, if you have bad teeth on the flex plate and the starter hits them and spins it chews the starter teeth some. That hurts the flex plate, and pretty soon everything is bad.