Hello All,
My 2001 F350 7.3 is giving me a fit.
A year and a half or so ago, I replaced the starter, on start up I had a quick hit and grind on the flex plate.
Only one hit and every start afterwards was fine. Well, I take that back, one out of every 200 starts would grind.
Fast forward to today. In the interim I have replaced both cables and new batteries. Just every 100 starts, flex plate grind. Also, the starter has also been replaced, the Nippondenso high torque unit.
In the past 2 months, I finally got down to replacing the flex plate, it had one area about 2 o'clock with damaged teeth. Replaced and thought my issues were behind me.
WRONG! Wife was in the drive thru and shut it down so she could be heard.
Took 3 tries to restart (grind) but away it went. Several weeks pass and no issues. I considered it being a fluke, perhaps she hit the starter with it running?
Nope, it did it tonight with me present. The wife is upset because I did have it taken care of locally ($) as I don't have the ability to drop the transmission where I'm at.
So, where do you think the failure point is? I thinking the starter, but if this were the issue, I think I would have multiple episodes around the flex plate.
It seems to get in one certain spot and that's were the issue occurs.
Everywhere else, perfect. Good engagement, good spin etc.

Any thoughts?

What my wife wants do to me right now.....

 

Mine also grinds once in a very long while no matter what starter I use, I am back to OEM now. It goes so long without grinding that I forget about it then one day it will do it. Subscribing to hopefully learn more.

 

Mine grinds rarely too. While the noise is irritating, is this something that can be fixed?

 

A faulty Bendix, or oil contamination won't let the Bendix go all the way out, causing the grinding sound.

 

Could it be a faulty casting on the engine so the starter mounts just a little too far from the flex plate? I remember in the far distant past some gas engine that had that problem.

Another possibility, more likely is low voltage to the starter. The starter draws so much current, that if one battery is starting to go bad, the other battery could have a problem providing enough juice to start properly. Or corroded cables or ground connections to the engine. When the voltage is low, the bendix may may not extend far enough to engage properly. But this is just a wild guess.

How about a bad starter relay on the passenger fender-do you have one of those?

The oil contamination as mentioned above is certainly a possibility.

 

Well mine just did it twice on Saturday and once on Sunday. It so happens that those have been two of our coldest days in a while too, under 50 degrees (I know I know, this is the desert OK?). I called my starter shop today and he said to bring it in and he'd replace the bendix. I thought about ordering the genuine Denso but I see the OP already tried that.

 

I did a lot of research today and it seems this is a very common issue. One interesting solution is a second relay to prevent the starter motor from turning before it is fully engaged to the ring gear. Check out post #4

Chewed up teeth on flywheel | Diesel Truck Forum - Oilburners.net

 

Excellent. I hope it was just a bad batch of pinions.

Leo