Limp mode/Transmission P/N 24208421

[NDT]

Undefined ratio error means this: The computer continually monitors the engine RPM (TISS) and the transmission output RPM (TOSS). Say for instance, in first gear, computer is expecting the ratio between the two sensors to be 6:1 for example. Then upon shifting to second, the ratio should be 4:1. Then upon shifting to third, ratio should be 2:1. But say the clutch pack slips, the solenoid is stuck, etc, and the ratio stays at 4:1. Computer says “oh no something is screwed, go to self preservation mode!!”which it does with limp mode, to prevent damage. The transmission shops will know how to fix this. Or you can dig deeper. Remember there is nothing military about the actual transmission itself. The controller is just a stand alone controller from a 1993 GM diesel vehicle that had no engine computer.

 

[ahowell9]

Undefined ratio error means this: The computer continually monitors the engine RPM (TISS) and the transmission output RPM (TOSS). Say for instance, in first gear, computer is expecting the ratio between the two sensors to be 6:1 for example. Then upon shifting to second, the ratio should be 4:1. Then upon shifting to third, ratio should be 2:1. But say the clutch pack slips, the solenoid is stuck, etc, and the ratio stays at 4:1. Computer says “oh no something is screwed, go to self preservation mode!!”which it does with limp mode, to prevent damage. The transmission shops will know how to fix this. Or you can dig deeper. Remember there is nothing military about the actual transmission itself. The controller is just a stand alone controller from a 1993 GM diesel vehicle that had no engine computer.

You rock brother! I'm getting it towed first thing tomorrow morning to a highly rated transmission shop a few miles away. Youvd definitely given me a piece of mind and some clarity to add.. thanks again