03 sterling 9513 transmission question

i purchased this 03 refurbished grapple truck at the beginning of September. It has a 450hp MB and an EF 8LL manual. The problem is that this truck was purchased for a driver that has since left the business and we have been trying to replace him for a couple of months. None of the other men that work for the company can drive a manual and I do not want to train them on my vehicles since most of our driving is city stop and go. We tried training in house years ago and either trained drivers that left to go OTR or to a competitor leaving us with the mechanics bill. So we are running a two pedal 6speed eaton Autoshift on a medium duty international chip truck and the men have no problems driving it other than reverse can be a little "jumpy". Is it possible to install an Autoshift unit aftermarket? I tried searching the eaton website and I think it is possible from what I read. If it is possible what would something like this cost and how much downtime would be required?