1998 LMTV 1079 Tranmsission Problems

[usaskeet]

Hello! I have a 1998 1079 w a wtec-III tranny that is throwing code 25-11. When starting to move it will show all 7 gears on the selector pad and will quickly only show 2nd gear and not move into any other gears. The truck has to be stopped and restarted to access any other gears including netural and reverse. I have ohm tested the speed sensor, checked tranny fluid, ran new wires from the speed sensor to the front of the cab, and swapped out the ecu, and put 4 new batteries in the truck. I am at a loss at this point. Does anyone have any thoughts on what the problem might be? I am desperately trying to get this fixed by Tuesday night.

 

[NDT]

Do you have a keypad you can swap out?

 

[Suprman]

Thats an output speed sensor related code. If replacing the sensor with a new one did not change symptoms and the wiring is known good it could still be a harness issue. I would check where the main harness mates to the pigtail coming off the trans. Look for corrosion or water infiltration into the connector. Look at the wiring on the harness itself see if the plastic sheathing is brittle and falling off that will cause intermittent shorts. Check the same on the front where it meets the cab harness drivers side of the hump behind the grill.

 

[usaskeet]

I do not have another selector pad.

There was certainly some brittle wires that were bare that I tried to "bandaid" by wrapping them in electrical tape and or replacing portions of the wire. This was especially present at the harness in front of the cab. I only ohm tested the speed sensor (it read 315), I did not have a new speed sensor to try. I was assuming that I need a new harness eventually, but will not help my current situation. I'm supposed be taking 8 kids fishing down the beach this weekend. Are they any available anywhere?

Thank you very much for the help

 

[Suprman]

I may have a decent used one. Brittle wires causing intermittent shorts are a very common issue on the trucks.

 

[usaskeet]

That would be amazing. If you do, please let me know how we can work it out.

Thanks again!!!

 

[wandering neurons]

Also check your power and ground leads for the transmission and keypad. I spent two months fussing with my RV, Cummins 8.3 turbo with a WTEC-II Allison transmission, same code, same symptoms. I used 14ga twisted shielded pair wiring to replace all three sensor wires from sensor to the back of the connector into the keypad. 38' RV, wintertime, and not much clearance underneath. Between the harness, and finding a loose power lead on the starter, the problem has been fixed. Good luck!