long story short i thought i'd ironed out all the bugs w/ my truck & decided to celebrate by taking it on a 220mi round trip to Mississippi & back... everything was going great, but heard a little bit of a rattle when stopping for gas about 70mi in.

got to my destination, noticing a bit more rattle anytime i was under 30mph. when i went to start the truck back up there was a horrible unholy noise like the flexplate was trying its hardest to escape. swearing and repeated attempts got the thing running- once i got to speed everything was fine & silent. i made it as far as Gulfport on the way home before i had to stop for gas again. once again it made horrible noises, then the starter was just spinning without engaging at all. finally a guy came along who had a breaker and turned the crank until it moved past the bad spot & started up again. still a little bit of a rattle but not as bad as before.

it should probably be noted that my old starter was missing a bolt (and died recently; i replaced starter & bolts); and i don't have a flywheel inspection plate- so lots of opportunities for that thing to get messed up.

drove back to new orleans noprob, and don't have time to do the huge amount of work it'll take to fix this right... at least, not anytime soon. what's the worst case scenario if i just keep driving around town like this, keep a big wrench in the cab to turn the crank if it won't start? toasted starter &/or potentially getting stranded? or something worse? at times it sounds almost like there's a protruding piece slamming against something else, or like something is dragging...

also, i read something in this forum about a starter shim- i don't really understand what it does/if it would help...?

 

Starter shims are chevy things. Bad teeth on your ring gear do not make noise once it is started and the starter disengages, a cracked flexplate will and can and will get worse.
I have seen them sound like a rod bearing is out.

 

so what happens if it gets worse? is it just that eventually i might not be able to start the truck, or is flexplate shrapnel going to take out more expensive parts of my drivetrain &/or the neighborhood?

i don't know what a bad rod bearing sounds like (knock on wood!), but it my first thought was that something like a large bolt had gotten wedged in there and was getting flung around (I don't think that's the issue, just trying to describe the noise).