B44.2 rear end spinning out

[The Bod]

Help required

On Friday night racing, the rear end on my B44.2 started slipping out severely when accelerating. The previous week all was running perfectly until i stripped my spur gear, so all that has changed is the new spur gear and obviously slipper settings.

I am guessing this is contributing to the fault ie an imbalance of power between the front and rear end. I think I set the slipper to the manual (2mm from slipper nut to end of shaft). Does this sound like a plausible reason for the rear end issues? What is the best slipper setting to use (2mm or other)?

Car is running foams, which previous week were 'glued' to the track.

Any suggestions/advice would be helpful