My father-in-law had a diesel Pup, and his transmission was also a problem for him. I've got a T5 Borg-Warner in mine, the same used with the 4.3L gas and the rest of the engine choises in an S10. Easy to find, and basically trouble-free. If you have constant tranny problems with the OEM style, converting over to this one, if it will even fit in the Pup chassis, would be one solution. Chev had diesel S10's, so the bell housing comes from there to mate to the T5. These T5's were used in S10/15, and with a different shifter location, in Camaro/Firebird/TransAm/etc, the Mustang for quite a few years, and even some of the older Jeep Cherokee had them. Plus other vehicles no doubt.
From what I've read, they were designed to handle up to 250hp, so I think we're all safe there, unless one of you have a secret project C223 you'd like to share with all of us....
