Starter issue

[72c20customcamper]

Well put anew starter in last week. Last one just clunked no spin or engagement of the bendix. The old starter had a few shims on the outside bolt to close the gap between the shaft and flexplate . I installed the rebuilt one it's a delco core had to shim outside bolt again to get the 1/8th gap. Everything was good truck started nicely . Wife went to move it today and it was grinding and kicking back on the starter. Shims still in and bolts still tight but I have a large gap again. I had even put in new starter bolts dont see how the starter could move. Not much I could do with my hand like this but I did add another shim to the outside bolt sounded much better and it started.

Anyone else experience this with a rebuilt? It's an autozone lifetime rebuilt in Mexico.

Since the old starter was shimed the same way I'm thinking I may need to take down the pad on the cone a little at a time till it's at least close to use small shim