Have an experienced mechanic listen to the starter as you engage it and crank the engine over. He can tell if the starter is to tight, to loose or just right. There is a process to measure the correct spacing between the starter drive and the flywheel. Not easily done by a non-mechanic.
Need to know why you think the starter needs to be shimed.
You shim the starter motor if there is inadequate clearance between the starter drive and the ring gear. You can check the clearance by prying the starter drive out to the ring gear with a screwdriver to see if the gears mesh properly.
Yes, if the drive gears are going too far in toward the flywheel because a shim is missing, you will damage either the starter gears, flywheel, or both.
Very rarely have to shim a starter. If there is excessive noise or a disengagement problem it will need to be shimmed.
starter gear is to close to flywheel install starter shim
No there is not a shim between the starter and the bolt holder unless someone has put the wrong starter on and had to rig it up to make it engage properly.
take off starter add shim directly under the 2 bolts, retorque bolts to spec
between starter housing & block
Shims bring the starter closer or further from the ring gear for proper alignment.
Disconnect the battery. Remove the outer bolt entirely. Loosen the inner bolt. Slide the starter shim in over the inner bolt and line it up with the outer bolt hole to get the outer bolt back in. Tighten the bolts. Start with a thin shim first and work your way bigger if needed.
you disconnect neg. side of battrey and then raise the truck and some times over the th rt front over the tire you can get to the wires to disconnect if not go under car and look at starter should be able to acess the wires only 2 of them then take the 2 mounting bolts for starter, remove them and then sneak the starter out it will be alittle tight to do so take your time. there might be a shim between starter and engine if so must use it with new starter unless the new starter may say no shim needed, would be printed on the head of starter. if no shim install with no shim. when installing and you connecting wires be sure that wires are not! touching together if not sure when you go to connect battery it will spark badleyand starter will engauge at that point leave battery disconneted double check wires at starter.