Waldo- Can you tell me on what page or sheet number in the assembly manual this part is shown? I have the manual but didn't see it on the rear suspension page.

Apache- I'm thinking the side of the truck with the spring spacer will effectively be lowered. This is because the shim puts the body of the truck lower to the ground with respect to the axle. So if the spacer is for compensation of the spare tire carrier and/or driver, then it makes sense to be on the passenger side only.

But I'd still like to see the part in the assembly manual! Hopefully Waldo53 can point me in the right direction!! Thanks everyone.