Transmission lights off and ignition death as well

[drmaeda]

hello; I am the owner of RV patriot Beaver 1995 40' with Cummings engine and Allison transmission. the transmission light went off and the engine can not be started. I wait for 20 min and the engine started as well as the transmission lights for few seconds and the transmission lights went off and the engine continue running until the ignition key was removed. restarted again and same thing happen. the light shows DO NOT SHIFT.
Transmission fluid level OK
temp in the transmission gauges OK
No other warning lights On

Any help Please

[NHRA225]

Since this is your 1st post on here I have to say Welcome aboard !
Now on to your problem.
Assuming the Trans is an MD3060 and assuming you've checked all of your Battery's and Grounds, you may have an issue with your Allison's TCU
If that's the case it needs to go to an Allison Professional to be diagnosed properly. Have you checked for codes ?

[RV Wizard]

Hello and We are glad to have you join us here and we look forward to reading of your adventures and experiences. I am sure you will enjoy our website and forums. Good luck, stay safe and keep us posted.
I can suggest you find a large truck garage that is highly recommended in your area to check the engine and transmission ECU's and inter connections via harnesses.

[kidz_driver]

There is an interconnect between the Allison transmission and the Cummins engine which prevents starting if the transmission ECU does not have power. Once started however it will continue to run until the fuel shutoff solenoid is activated.

Something is causing you transmission to lose power after a few moments of powering on, possibly a bad ground, a bad +supply or the ECU. The Allison ECU is fed by a dedicated fused line connected to the chassis battery. Corrosion of the fuse and/or the line connectors can cause intermittent problems such as yours. Before going to the expense of a tow to the shop, verify that your transmission ECU is well grounded and is getting power both at the fuse and at the ECU.

[drmaeda]

the technician found that the problem was the Allison ECU and sent it to transmission Instruments for repair. I hope this resolves the problem. thank you for your help

[RV Wizard]

You are welcome and thank you for keeping us posted.

[jdoran1973]

Hope they can get this issue resolved now that they have an idea of what is going on. Good luck.

[mel s]

Originally Posted by drmaeda

hello; I am the owner of RV patriot Beaver 1995 40' with Cummings engine and Allison transmission. the transmission light went off and the engine can not be started. I wait for 20 min and the engine started as well as the transmission lights for few seconds and the transmission lights went off and the engine continue running until the ignition key was removed. restarted again and same thing happen. the light shows DO NOT SHIFT.
Transmission fluid level OK
temp in the transmission gauges OK
No other warning lights On

Any help Please

I had that DO NOT SHIFT display happen twice!
Once it was a corroded in-line fuse near the + terminal of the chassis battery.
The other time the wire from the chassis battery + terminal to the Allison VIM:

was bad and had to be replaced.
Mel
'96 Safari, M3060 Allison

[deandec]

I had similar symptoms about 5 weeks ago. Except it was not intermittent like yours.

The resolution was improving the ground contact for the Ignition Solenoid (not the starter solenoid).