Starter/Flexplate issues

[Gabriel Morris-Iken]

I have an '86 Ranger 2.9L RWD with an automatic transmission that's having trouble with the starter. I replaced it just a few months ago, and it worked great with no issues. About a week ago it started making a terrible grinding noise the first time I went to start the truck, then I would try again and it would start fine. A few days went by of this grinding then, I tried to start the truck and it was free spinning.

So I checked the flex plate teeth after taking the starter off, and most of the teeth are somewhat worn, mostly okay, but one tooth on was chipped pretty bad, on both the flex plate and the starter (one tooth each). Will this cause damage to a new starter if I go ahead and replace it again? The flex plate teeth aren't terrible, minus that one problem tooth, and I don't want to replace it if I don't have to, but I'm concerned I'll just be burning through starters until I replace the flex plate. Thoughts?

Note, neither the starter I took off, nor the new starter, came with shims. Is it possible I need shims to ensure the teeth of the starter pinion engage with the flex plate?

Thanks-

 

[RonD]

Welcome to the forum

Yes, this is a fairly common issue for the 2.9l 1986-1989 starters

There is a "Block plate" or "separator plate" between the bell housing and engine, it has a hole to keep starter motor's nose in the correct position
This "plate" can either be left out or worn so nose can shift position, the bolts and holes are not precise enough to keep starter from shifting position, a lot of torque there when starter motor is working
We are talking about 37 year old alignment here, lol

Yes, thin washers/shims between starter motor and bell housing can help align depth, especially if block plate is missing
People have also used shims in starter motor bolt holes to off set starter towards or away from ring gear

Cut up a beer/soda can then put crescent moon shape, "C", in the bolt holes so starter can't shift positions
Pull starter out, put bolts in each hole so you can see how thick a shim needs to be so bolt is tight in the hole, no wiggle room

If you change starters you have to do this again since each casting will be slightly different, even from same maker of starter motors

 

[Gabriel Morris-Iken]

Thanks so much for the detailed answer!

 

[2 bronco 11s]

Had that problem. Does that starter require shouldered bolts? The new ones bolt hole are to big which allows the starter to move after awhile. The 2 I have replaced on the Bronco 11s both had a sticker on the side showing this bolt.