Allison 3000 in a 3800 IH, intermittent problem with shifting. once or twice a week it throws a fit and will not shift gears. driver does not notice anything until they try to go into reverse and it stays in a forward gear, usually 4th, and will stay in that gear even when you shift lever to neutral or any other position. If you shut the bus off and restart it starts working fine for a bit before acting up again. The only code I can get from the shifter is 5655. On a side note this bus' volt gauge only reads 12.8v when running but I have 14.3v at the batteries. could all of this be from a bad key switch? I have a new key switch coming in the morning to try but has anyone had this issue before?
Thanks Krmvcs, I have that booklet. all connections and wires appear to be in good condition. I wiggled the wires at the back of the ignition switch and the volt gauge jumped up for a sec and fell back down. I am going to replace the ign switch in the morning and take it for a test drive.
*update* the new key switch fixed my voltage gauge problem but did nothing for my trans issue. I took the bus for a test drive and I was able to get it to act up once the fluid got to about 140*F. This time it stuck in first gear, while it was stuck in gear I was able to pull a 2215 code for turbine speed sensor. I shut the bus off and restarted and the trans shifted normally again till I got it back to the shop. I then dropped the valve body assy. and removed the turbine speed sensor. I had a new sensor in stock so I checked resistance of old sensor and compared it to the new sensor. The old sensor was open and the new sensor had 333ohms of resistance. I think I may have found my problem... I will update tomorrow when my gasket kit comes in and I get it back together.
*update* turbine speed sensor was my problem, the transmission operates great now. Replacing the sensor was much easier than I thought it would be, just time consuming.