96 fuso fe-Sp

I have a 1996 fuso fe-sp, I took it in to a local shop for service and transmission check as it was not shifting up and locking up in reverse. After servicing and the transmission inspection,I was told the transmission was in need of replacement. So the company sourced a rebuild and installed it, that unit failed and the supplier sent out parts to fix the issues, this did not work. So the unit was removed and sent back to the supplier. They renewed it ? And sent it back, same issues! Now they are arguing with the supplier and have now told me the turbo is bad ( stuck open waste gate) and they are claiming this is causing the transmission to not operate properly.
this has been on going for over four months.

any experience or advice?

I would suggesting starting with this link, in an effort to learn more about the powertrain and help your technician with a proper diagnosis.

https://duckduckgo.com/?t=ffab&q=199...agnosis&ia=web

It seems the old problem we as GM diesel owners went through in years past also seems to affect all diesel owners to some degree. Learning as much as you can about your truck and its engine/trans can help you help your diesel tech... Be patient, be thoughtful and be persistent with him. Don't tell him that "I read this on the internet". Speak as though you know more than a typical customer... The more you know, the more likely you'll get good service.

Let us know what happens...
Jim