I have a 12 valve cummins and it had a full trans rebuild including a 3 disc converter valve body master kit billet accum servo timing gsk governor solenoid and transducer totaling about 4,500 , about 80,000 miles ago and it's slipping bad in second gear when I accelerate it will hang up in first gear thin when it hits second gear it will jump from 1,000 to 2,000 rpm and for a good 15 seconds thin shift and won't do it again till I shut my truck off it shifts smooth and has no other problems going into gear Other than second it has been sitting for about 6 months not moving because of my d.u.i so idk if that has something to do with it please help I need the truck for work and I'm worried to drive it to cause any further damage

 

In second gear is where the problem is so that is the second gear band. I would wont to check oil pressure at that gear to see what it is . My truck is a 95 so it not controlled electrical circuits in that shift. I would never let one slip like that if I could help it . If it does not hold or you suspect a engine flare up get off the throttle as soon as possible. If you lost second gear and it did not come back I would wont to check the second gear strut and anchor . Pulling the pan and checking the band adjustment. If you can get a gauge and check oil pressure in the second gear port

 

Zac, we need the year of the truck, as working man says, 94 and 95 are 100 percent hydraulic, starting in 96 they went to the RE which put lone pressure control in the computer.