I have an Allison MD 3060(1998-1999) on a 1999 Dutch Star motorhome with FreightLiner XC chassis and Cat 3126B engine. On a recent 3200 mile trip one cold(20F) morning the Check Trans light came on right after start.
The tranny would not shift from neutral(electronic control pad). Thinking that this was simply a cold weather anomaly I shut down, restarted and everything returned to normal for the remainder of the trip(~1500 miles).
After returning home and parking in my driveway for a few days, the same problem has recurred but will not clear and the tranny will not shift from neutral. Checking the diagnostic codes reveals a 45(open condition in solenoid circuit) followed by 16(E solenoid) which will not clear by the method in the manual…holding the mode switch down for several seconds. When doing this, the Check Trans light
does flicker off and then immediately back on so I assume that this means that the code is briefly cleared and then
immediately reappears. My local Allison dealer was kind enough to fax me four pages from the diagnostic manual that describes the circuits involved and the recommended troubleshooting procedures. Checking for an open on the T-connector(disconnected from the ECU) at the ECU shows ~3.2 ohms…i.e. no open.
The connector looks clean with no damage. Cleaning the connector and reconnecting leaves the same error. This leads me to think that the problem is in the ECU but bothers me to think that a single circuit would fail with no other apparent ECU problems.
Does anyone here have any ideas on how I should proceed? Been there, done that???
Thanks for any help…
Tom Fisher
Dallas,TX