[racingdwarf]

diff shims? you should know about them! your a rallyx man. I would say the last owner had it in there to stop the diff floating about,with a car with crown wheel and pinion drive, most rallyx and a large number of 10th 4wd they are vital to adjust the back lash/mesh of the gears,but with the common 2wd diff layout of layshaft style drive gears to diff your don't realy need to worry about a small amount of end float,IMO you realy want a nice free transmission little play not a prob.

Have a look at the gearbox housings,there maybe a chance the last owner had a bearing problem that damaged the housings,thus the shim, as in most of my cars inc the mad monkey the bearings are a nice snug fit...just a thought