1990 4.9L I-6 with EOD4 tranny (a rebuilt unit from Jasper, put on b4 I bought the truck). I haven't yet towed my boat with it, but the truck seems to upshift at real low rpms (unless you're really hard on the gas). What's involved with changing the shift points? A shift kit, or more involved than that? I assume that somebody out there has done this. Tires are stock size. Gearing is 3.56 I believe (or something close to that).

 

You would have to reprogram the computer, there's no kick down cable or anything mechanical to adjust. A hypertech power programmer lets you change shiftpoints but i believe those are only for GM's. Maybe you could get a custom superchip. I don't see why there would be a need to change it though, these trucks are made to tow. Maybe the computer will learn new shiftpoints while you tow?? I don't know i never really paid attention to it while towing, but i haven't had any problems.

-Jon