I would be having a look at the setup of the transmission build and have a look at why selector travel may be now reduced over factory. This is why when we limit selector travel with WR35GS we do it at the shift piston, rather than having the lever moment of braking the selector come back through its cast body. As for the selector we have this part drawn on CAD, its a matter of whether you want to commission us to machine a billet piece for you. Regardless of who/what shift selector you use to repair the transmission, address the problem of the selector over travelling to prevent further carnage.
Can it be because of 800hp clutch pack. Because it stalls when you slow the vehicle and when moving from standing still the car wants speed but when you are in a traffic jam you cant move at an idle speed. The car stalls at speeds 5-10kmh
Every broken selector issue we have come across is due to an incorrect clearance in the transmission. The selectors arent particularly strong, and having them hammer into the synchro dog stop constantly will eventually cause this kind of failure. The way it works is that the TCM signals the transmission electronics which move the hydraulic pistons, which actuate the top of the selector (where this one broke) which them forces the shift and slams up against the synchro dog stopper. This is why we limit the movement of the hydraulic piston right back at the source of the shift so that big shock loadings arent going back through selector arrangement. 'Short Shifter' designers for manual transmissions have been doing this for years - limit the travel - and save the selector assembly from 'overselection'
Regardless there is something terribly wrong with your clutch setup, what type is it?