XRAY - Model racing cars

I am in the process of building an xb808e and was wondering the best way to determine proper gear mesh in the front and rear transmissions. Is it by feel? With the pinion gear and diff gear somewhat visually obscured by the housing, I can't see all that well. Any advise?

It's by feel. For new XB808 I didn't have to use any shims. After some running I added 0.1mm to crown gear side to decrease the gap.

Read through all the FAQ threads, there's lot of valuable information.

Go to your local car dealership and stop by the parts department and ask for a tube of gear marking compound. Most is yellow these days but any color will work. Set it up where you think it feels best and then brush a light amount around the entire ring gear. Put it back togeather and hold one outdrive still while turning the pinion. This will load the gear set and make an accurate impression of the current contact. Take it apart and see what you have.

Center of the tooth is what your looking for. Hope this helps. This is the actual procedure used in automotive aplications but it works exactly the same on these smaller gear sets.