Wonder if you can stuff a 6l90E in your rig. Better gearing, better miles out of the trans overall.......Sorry to say I am not surprised. ALL of the TH400/4l80E transmissions I have had behind BB V8's doing heavy duty towing and hauling have averaged 30-35K between rebuilds! That too is with 5K flushes and filter changes. First gear is way the hecko to tall for getting loads moving. hence it will heat up with out trying. I have a 95K on y 2000 C2500 with a 350. But it has not had near as hard a life as the BB setups did. This is mostly a grocery getter, smaller 3500 lb single axel mower trailer puller. BUT, it still has to go up some steeper 15-20% grades to get to job sites.
Marty
