I forget which truck i had these on, but i cant find them on any of the exploded views on the E/revo platform.
I removed the rockers once and some spacers fell out from under the rockers on the rear. Im trying to find them again, on pretty much all my Revo based rides the rear spring preload rings are very difficult to turn and adjust preload. I would tend to believe that that little spacer would help this issue.

Anyone have a part #?

Short of that, anyone have a quick fix for the rear preload rings?

Fronts have given me zero issues on any of my rigs, but those rears are a nail buster.