can anyone tell me why a au dash cluster series 1 or 2 wont go into a series 1 au whats the diff ?

if i recall the measurements between the speed increments changed ever so slightly on au2 onwards. so if you put an au2 cluster in an au1 it will give incorrect speeds. ive never verified this but its what i got told by 2 different wreckers i tried sourcing an au xr cluster from once before.

Like Ash says, they don't work too well together. If you plug the AUII/III into AUI you won't be getting very much to work.