The problem is that the hole in the centre of the spur is about 1/2mm diameter bigger than the shaft.
The spur does look like it's been slipping for ages. Just now I tried to set the slipper as per the manual & had the slipper nut jump and slip down the layshaft. The thread looks knackered so no surprise there. I guess the nut's been jumping in use, killing the spur. I'll be getting a new spur, but was a little shocked at the price of a new layshaft. Having said that, it's not something you'd normally need to replace......
I'm going to try a new nut and keep my fingers crossed.
I tend to use 10x2 / 9x2 brushed Checkpoints in my 4wd, so with that in mind, is a 108 spur the best overall choice with the XX4 pulley? What size pinion for a 10 turn?
Next question: the car is fitted with narrow alloy rear pivot blocks (from a Losi 2WD?) so that the wishbone pivot pins sit closer to the centre line of the car than my XX4. The wheel hubs are fitted to the outside pair of holes on the new style rr wishbones.
As the driveshafts only just sit in the rear diff outdrives, I'm guessing this makes the rear of the car wider than standard. Any clues what this does to the handling? Am I better off with the standard XX4 setup?