That is an XTM diff. I didn't think I explained what I was trying to say well enough so I linked to a picture to show what I was talking about. The way you explained it, it sounded like you were having problems with the 43t gear and the 13t pinion. What that mod does is to limit the 43t gear from moving around on the diff.

Have you tried the machined cross shaft? http://www.ehobbies.com/rc-cen-ffs027.html
I used to break them all of the time untill I upgraded to the ffs027 part. I also shimmed the side gears in the diff a little tight but not binding to limit the excess slop in the three little gears. Then I shimmed the diff to pinion clearance again a little tight but not binding.


rolland