96 12 valve issues

[mdmike]

I had the same problem on a 96 cummins. My issue was a wire close to the big plug on the side of the trans was broken inside the coating. No visible outside damage to the wires. I felt along the wires, pinching them between my fingernails, before I felt a soft spot in one of the wires. Cut the soft spot out and spliced it back and trans shifted normal again.

I had the same thing happen on my 97.

If I started the truck and put it in drive, I would have one 1st gear take-off then the trans would go into limp mode from there. Mine was a broken wire between the trans and the computer on the firewall. I had replaced just about every other pig tail before I gave up and took it to the local transmission shop.

I was this >< close to swapping an nv4500 in it.

 

[Projectjunkie]

There's also some mod called a "mystery switch" iirc. I found it while beating my head against the wall on shifting issues. You wire in a toggle switch or switches as a redundant system to get you home, not for everyday driving since it's always locked up, or runs full line pressure, I forget what exactly. But, it might be helpful in this case to verify that the trans is OK

 

[kschaper75]

There's also some mod called a "mystery switch" iirc. I found it while beating my head against the wall on shifting issues. You wire in a toggle switch or switches as a redundant system to get you home, not for everyday driving since it's always locked up, or runs full line pressure, I forget what exactly. But, it might be helpful in this case to verify that the trans is OK

I think he did something like that already. I'll have to ask