Hi there, My dad bought a 91 intercooled d250 cummins auto last year, just to use pulling his little camper maybe 4000lbs. The truck could barely pull it. We had the auto built goerend converter some sort of shift kit and some other stuff, now it worked a lot better but still didnt really pull it like a cummins should, now i know hes limited by the auto modified or not lack of traction and being bone stock other than straight piped and bhaf, but i have to wonder back in the day what could these really pull when stock? i have never had a first gen i have a 01 24 valve 6 speed and i have pulled 3 bobcats with ease, now my truck is heavily modified, but i just dont understand why my wifes 05 hemi also 2wd pulls that little camper way easier than that first gen, dosent make sense that you hve to modify it a bunch just to pull 4000lbs it is a cummins after all!! truck has 196000 miles.