Hello, I'm Chris. Thanks for seeking us for help.
When the failure occurs tell me what sounds you get or what is happening?
Are you installing Motorcraft parts?
I get a grinding noise. Then it might or might not start. Depends on how many times I try to start it. The last flex plate was ordered from Ford the last time. I am not sure about the starter.
I assume when you remove the transmission and flex plate, you find the flex plate teeth ground off?
Yes that is correct
Do you have a repair order showing how much you paid for the starters so I can see if there cheap after markets or Motorcraft?
Have you ever noticed once it has started the starter stays engaged?
Not home now to look but pretty sure the starter was not Motorcraft. The starter does not stay engaged after I start it.
Most likely your starters your using are rebuilt poorly and not engaging the flex plate fully resulting in the flex plate failing. The only other cause would be a crankshaft thrust bearing failure allowing the flex plate to move in and out towards the engine and transmission. However we rarely ever see that, but it is the only other thing to blame. The last thing to check would be a cracked bellhousing allowing the starter to flex away at an angle when being used.
So if they were not rebuilt starters then it only leaves the last 2 options and if it isn't either of those then I should replace with Motorcraft parts? Do the Mototcraft parts come with a warranty?
All Motorcraft parts have a parts and labor warranty.
Yes if its a Motorcraft starter then you need to let Ford diagnose and fix this issue, since the parts are covered.
With Ford parts on it, I can only see the cracked bellhousing or thrust bearings to blame.
I am getting the truck looked at tomorrow so I will know more after that if I have any other questions. Thanks so much for checking back.
My mechanic went to the local ford dealer to get a new Motorcraft starter and was told they only make rebuilt or refab not new. Is this correct. Should I use the rebuilt Motorcraft starter?
That is a correct, a Motorcraft branded factory remanufactured starter is what is needed.