Starter Shims 89 Wrangler

I bought a new starter for my 89 Wrangler. In the box was a bulletin stating that Jeep Wranglers up to 1994 requires a .015 shim. Wranglers after 1994 requires a .042 shim. My first question is; has anyone heard about adding shims to Jeep Wranglers and is it required for all Jeep Wranglers? My second question is; how do I know if I even need shims?

Wow, im having the exact same issue, I have the same question. I'm super bummed that this post is 10yrs old and has not got even one reply!!
:nono:

I haven't worked on an 89 Wrangler but normally if the Bendix sticks a shim is needed. As the gear goes into the flywheel and hangs up a shim is needed.
If a shim is used on the starter you took out use it if it was working properly.

I'm having the same issue on an '87 yj. Second starter in 6 months. The starter gears are grinding off and appears only 1/4" of starter gear is engaging with the flywheel. I was going to try shims, but have no idea.
If anyone has any suggestions I would much appreciate it.

Try an .015 shim and if the bendix sticks occasionally add another one.