RE: allison transmission
john carroll - 9/27/2009 11:06 PM
Drove approx 50 miles, no problems. Stopped, put on brake and put in neutural. Shifter said 6 N. Transmission would not go into drive or reverse. Jacks were not down, foot was on the brake. Later it went in to drive with no problem. Do you have any suggestions or remedies??
Very difficult to say exactly what happened because it's not happening now and there is more than one possibility.
Here's what I do know. When you see the shifter say 6 N. That means it sees you have selected 6, but the controller is not allowing the shift to drive. Select 6, Attain N. That means there was some kind of inhibit that the TCM thought was active.
It could have thought the engine idle was too high, maybe the brake switch wasn't closing all the way or an intermittent in a wire, maybe there was an intermittent in the jacks system.
If it were mine, I'd find out what air switch is in the brake system that's used for neutral to range inhibit and carry a spare switch(assuming the vehicle has air brakes).
I'd also inspect the related wiring to the switch, the jacks, and any other system in the vehicle that can cause a neutral to range inhibit.
