You need to use a shim to avoid noises that the starter emits. There may be the many reasons for the starter noise including the starter may be too far or too close to flywheel teeth, loose mounting bolts and much more. ... But sometimes the starters require shims to keep the drive gear away from the flex tape gear.

How many shims does a Chevy starter have?

Note: Do not use more than 3 shims on either side. When installing replacement starter motor: DO NOT use an impact gun or breaker bar to tighten bolts!

What would make a starter not engage?

A weak click means there is a loose connection. Check the wires that connect to your starter solenoid and tighten them. In the case of broken wires, electrical current from your battery will not reach the starter. If the wires are in place and still your car will not start, then you must replace the starter solenoid.