94 pickup V6 4WD. The starter worked for a few months fine, and for the last two months has been emitting a grinding noise when I crank. After a few tries it will start like normal. Sometimes it starts first try, sometimes I'm afraid it won't start.
I wonder if the drive of the starter is going out, or if some teeth are worn out? It is winter here, so it's been through temperatures from -15F to 32 so far, and it hasn't really changed based on the coldness. I couldn't find anything like my problem on the archives.

 

Has any bolts backed loose that hold the starter? Sounds like you could have some broken teeth on the flywheel. It only takes one or two broken teeth for it to do that. It if stops in a good place on the flywheel the momentum will usually keep it rotating til it get back in good teeth. That is why some time it starts with no problem and other times it grinds.

 

Does it ever grind for a split second after the engine starts? If so It could just be that because of the cold temperatures the grease in the starter is super thick to the point where the starter is not disengaging right away. Also, it could be the opposite where the cold grease is not allowing it to engage all the way. Either way it can cause damage and break teeth. It's happening to a car I have right now early in the morning when it's really frigid.

 

Oh, to see if the bolts backed out, (it's happens to mine on two different occasions) it's kinda a bitch but you can actually cut your wheels to the left all the way, reach your arm in the wheel well of the front passenger side, and see if you can wiggle the starter. If it has any play at all, you'll know you need to tighten the bolts. Also, if it has play, hold the starter so it's firmly pressed where it should be, have someone else attempt to start it, and see if it still makes the grinding noise.

 

I had an issue similar to yours, if its super cold outside the bendix on my starter would not disengage from the flywheel and it would grind for a second once the engine was started.

A new starter fixed the problem

VIDEO:

22re starter noise - YouTube

 

It doesn't continue to grind after starting, just during the cranking process. I'm gonna pull it off tomorrow and have a look at it. Missing teeth on the starter gear makes sense to me, but I've also heard that it could be whatever engages with the starter to turn it, i.e. a smaller internal-to-starter gear that's grinding. Which could make sense too.

 

i had a started that only worked 3 out of ten times cause it had missing teeth... was a pita

 

I had an old chevy s-10 that I swapped a 350 into (sweet truck btw) I burned up the first tranny and replaced it, on startup the starter would occasionally grind on the flexplate maybe 45% of the time. No broken teeth but turned out that when i removed the tranny the converter hit the flexplate ever so slightly which bent it on one side, starter would have a really hard time engaging on that side.

 

I've been told that the flywheel on a vehicle stops in 4 (V8), 3 (V6), or 2 (4 cyl) places every time due to the compression of the cylinders as the engine stops. Meaning it may turn backwards at the very end to compensate for said compression. Unfortunately, this means that even if your starter teeth are worn (as they are usually softer than your flywheel) and you replace it, your flywheel is worn and will need to be replaced. I have had this happen on 3 vehicles. Lucky me Pull your starter and look at your flywheel (if possible). That will tell you really quickly if that's your problem or not as it's pretty obvious when looking at the flywheel teeth. I suppose you could just keep a breaker bar with the appropriate socket in the truck and turn it a bit before starting...

 

I replaced the starter and everything is good. The flywheel wasn't worn. We think the bendix was grinding somewhere.