How to resolve a twitchy back-end in 1/8 buggy?

[VintageMA]

Originally Posted by BrianG

What diff fluid do you have in the back? Maybe too thick?

I'm trying to remember as it has been a while since I did the setup. I know I changed the fluids a few months back, but can't find the sheet I was tracking the setup on.

I think I am running 5/20/2 (although I may have upped it to 3k in the rear).