XRAY - Model racing cars

Hi,

I am running a gear centre diff (364901) on my 2018 Xray Xb4. I have been wearing through spur gears way too fast - usually go through one every club day or so.

I have recently purchased a XB4 2019 and have started building it. As the centre diff is on order from supplier I have used the slipper instead for now.

As soon as I installed the slipper I noticed what the problem is - The gear diff sits too close to the motor plate causing it to not mesh properly with the pinion. When I place the slipper and gear diff side by side vertically on a table you can clearly see the spur gear sits 1mm higher on the gear diff.

Thinking it was an assembly problem I completely stripped and rebuilt the diff (changed the diff housing, pins, top housing and spur in the process). However, its still definitely 1mm higher than the slipper (sits right next to the carbon fibre surround instead of in the middle).

Anyone else experienced this? I expect the problem is the lower housing needs to be 1mm shorter and the upper housing 1mm longer for the spur to sit properly on this car.