We cannot keep starters on our 1978 in-line six F-350 airport fuel delivery truck. A NAPA or Car Quest rebuilt starter lasts about 6 months before it refuses to engage. The starter motor runs strongly but the gears grind and do not engage. The flywheel was replaced this year along with the starter and the starter just bit the dust again. We have installed them with and with out shims. It didn't seem to make any difference. The transmission is a manual 4 speed.

There seems to be something systematically wrong with this set up. I'm ready to try a Ford new starter if I can get one but have no confidence that will solve the problem.

Any ideas???

 

I should have looked first this time. Starter bolts were loose.

 

Need to locktite the starter bolts on a six.