Allison 3000RDS

[Pappy61]

I have an Ottawa yard mule giving me grief. It would no shift into any gear and move it stays in neutral regardless where I put the selector fluid level is good and I replace the harness from the trans controller all the way to the transmission. With no results. Any help here would be appreciated

 

[Hino123]

It sounds like it has an active shift inhibit. Make sure the TCM fuses are good. If it is a push button shift selector can you pull the fault codes? Could be power, ground, or a can communication fault. Need more info to help further.

 

[Pappy61]

Ok this truck has the shift lever that allows me to pull the codes the one thing that I noticed was the oil level was high by 1 quart and a P2686 code that was why I replaced the complete harness from the TCM to the transmission. I know the transmission will not shift if the oil level is low. Could it do this being over full. All fuses are good that I can find .

 

[Hino123]

Here is the troubleshooting guide.

 

[Hino123]

Looks like the High side driver is seeing high voltage. If you have already replaced the external harness with a new on that leaves.... a faulty TCM, or an internal fault with the wiring. If you had a test TCM that would eliminate the TCM at least. Be sure to check pin drag and inspect all the pins associated with the code well. A fluid level that is slightly high or low will not set this code. The TCM is seeing over 6v on the return wire when the driver is powered down. It sees this voltage and that’s when it sets. Let us know what you find.