2003 f150 4.2l starter staying engaged.

I'm trying to figure this out. replaced an engine and transmission on my truck and starter was hanging. Ford told me that it was my flywheel so I changed it and it keeps burning up starters. It will stay engaged. It is a Ford flywheel and a Ford starter.

 

need a little more info ?

what do you mean by, the starter stays engaged ?
is the started stating electrically energized ?

does the snout of the starter fit snugly in the opening of the separator plate
( thin plate between the engine,& trans) ?

does the engine have both dowel pins in the trans mounting surface?

 

I was reading over on the Ford forums. Some wacky theories over there.

You're certain that the starter is staying mechanically engaged and not due from an electrical short or solenoid problem.

GM had a problem with the starter teeth meshing too tightly with the flywheel and either causing some grinding or the starter gear would get stuck out. They had shim plates that were installed between the starter and the block. I've never heard of that being done on a Ford.

My first guess would be to say a defective starter but apparently you've gone thru several ?