It good to know that i'm not alone, although i don't have any problems with the internal gears. It's only the bevel gear (I stripped one 35T diff gear though), the mesh shouldn't be that thight because higher temperatures in the diff will make the mesh tighter. That said and the comments on the XRAY forum leads me to the conclusion that they have some homework to do. Funny that they don't want to comment on it, but meanwhile the bevel gear is probably the most sold and sought after part for the XB4.
Well hope they find a proper solution... And more I hope that my ordered XB9E is problem free in the driveline....