My Allison World Transmission in my 1994 motorhome is acting up. Specifically the Transmission Control Module. When I

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Customer: My Allison World Transmission in my 1994 motorhome is acting up. Specifically the Transmission Control Module. When I start the motorhome, the shift control pad will light up for less than 30 seconds, I can select a gear at that time, however, it starts to blink and then goes blank, while a do not shift light illuminates on the dash. Trying to pinpoint if it is a interrupted power issue, the TCM going bad, a relay, bad wire connection, or fuse.
JA: Have you checked the fuses? The dashboard bulbs?
Customer: I do not have a schematic for my coach's fuses (due to the age). The dashboard bulbs all work.
JA: What is the model of your '94 transmissions?
Customer: I'm thinking it is an Allison 2000. The has 3 displays. The current gear it is in on the left, mode light in the middle, and the gear I have selected (by using up and down arrows) on the right of the display8.
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: Yes, It is stuck in my steel building, and I am located approximately 30 to 40 miles from any technician. I have been looking for bad wire connections. However, this is daunting as there is about 20,000 miles of wire, and wire harnesses about 4-5 inches around. I have located the Allison panel with 6 12v relays inside. I have yet to disconnect it from the wall to check the internal fuse. I have also cleaned the connectors at the transmission, and have unplugged and plugged back in the 2 huge connectors at the bottom of the TCM
JA: Anything else you want the mechanic to know before I connect you?
Customer: This problem presented itself a couple of week ago when I went to fuel up before driving it to an RV park which was about 150 miles away. The TCM was blinking with the do not shift button illuminating on the dash. After a few minutes of turning off the motorhome and restarting. The TCM display stayed steady. I drove, got the fuel and returned home. The next day I drove to the RV park without any incident. A few days later when I started the motorhome to go home. I had the blinking to blank TCM display with the do not shift button. It sounded like I could hear a relay underneath the dash clicking, hard to tell when the motorhome was started due to the engine noise. It took me about an hour before it finally stopped blinking, I drove home, and a few days later no problem in putting it back in my building. I need to drive about 500 miles, as I purchased a new motorhome and I need to get this to the dealer for my trade-in. I also don't want to be stranded on the freeway, if the problem started again while driving. I'd be pretty much stuck in whatever lane I was in.
Answered by Daniel Wilson in 1 day 5 years ago
Daniel Wilson
Auto Mechanic

20,000 satisfied customers

Specialities include: Auto Body Technician, Heavy Equipment Repairs, Heavy Duty Engine Repairs, Brake and Transmission Repairs

Hi my name is***** you still need help with this? If so let me know. We can follow up as needed.

I do. I never received an answer, I've been waiting. Allison TouchPad lights up for about 20 seconds, blinks, then goes dark. Do not shift light comes on. I replaced ignition solenoid. Been checking wires and connections. Might be related, inverter just clicks when selected. Disconnected house batteries, interior lights still come on. Pushed inverter button, heard fan for a few seconds, then clicks again. Problem with battery isolator? Would isolator also affect Allison ECU?
I think the transmission problem and the inverter problem are separate. The transmission pad was acting up prior to me going to get fuel. I was able to drive the 10 miles, fuel up, and return without any problem. The next night I was in a hurry and forgot to unplug the coach from shore power. It pulled the cord out of the white plastic housing (broke the housing). The cord was pulled out about 1 foot. It might have pulled some wires in the transfer switch. I'll look at that tomorrow. Probably a wire is hot in there as well. When I was cleaning the coach, I was polishing the wheels, I got shocked off the left rear wheel (nearest the transfer switch). It was just low grade tingling shock on my hand.Still might have a problem with the isolator however, as the coach lights are on with the house batteries disconnected.My biggest concern is getting the Allison pad to stay lit, and in gear, so I can drive it. I purchased a newer coach in Oregon and I need to deliver this coach to them on the 27th of November. I have 10 days to get this figured out. They know about the problem and gave me this extra time to get it figured out.

I recommend having it scanned for fault codes with the Prolink software.

If the ECU detects a serious transmission fault, the DO NOT SHIFT light (usually located on the vehicle instrument
panel) illuminates, the shift selector sounds short beeps for eight seconds, and the SELECT digit on the shift selector
display becomes blank. Transmission shifting is restricted while the DO NOT SHIFT light is illuminated. The ECU
will not respond to shift selector requests including direction changes and shifts to or from Neutral.
If the shift selector lever is moved while DO NOT SHIFT is illuminated, a continuous alarm will sound until the
lever is moved back to the position where DO NOT SHIFT was first indicated. Normal shift selector operation is
restored when the conditions causing the DO NOT SHIFT alarm are corrected.
The ECU will log a diagnostic code when the DO NOT SHIFT light is illuminated. Use the shift selector display
or the Pro-Link® 9000 Diagnostic Tool to display the diagnostic code. Codes related to the DO NOT SHIFT light
are detailed in the code chart (refer to Section 6).
The current Diagnostic Data Reader (DDR) is the Pro-Link® 9000 (J 38538-D) diagnostic tool which is available
through Kent-Moore Heavy-Duty Division. A portable microcomputer-based receiver/transmitter/display unit, the
Pro-Link® transmits and receives data to and from the ECU, processes the data, and displays appropriate
information. Use the Pro-Link® during installation checkout and troubleshooting. There is a new Pro-Link®
cartridge needed for use with WTEC III controls. The new Multi-Protocol Cartridge (MPC) contains a
programmed PCMCIA card which allows for reprogramming of GPI/GPO packages. Reprogramming includes
selection of a GPI/GPO package, enabling/disabling of wires, and modification of certain data parameters.
Operating instructions are supplied with each Pro-Link® and further information is also included in Appendix N of
this manual. Connect the Pro-Link® 9000 to the diagnostic connector provided in the selector wiring harness.
NOTE: The new MPC is usable with WTEC II controls but the old WTEC II reprogramming cartridge will
not display the WTEC III new information. The new MPC must be used to reprogram WTEC III
Tool part numbers for the Pro-Link® are as follows:
Diagnostic Kit J 38538D + J 38500-313 (PROM Update) = J 38538E
Diagnostic Cartridge J 38500-302 + J 38500-313 = J 38500-303
MPC J###-##-####
PCMCIA (Diagnostic And Reprogramming) J###-##-####
PCMCIA (Diagnostic Only) J###-##-####

I can help with the service book as well if interested. Im logging out for the night but will be on tomorrow throughout the day for follow ups,

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Daniel Wilson
20,000 satisfied customers
Auto Mechanic
Daniel Wilson
Auto Mechanic

20,000 satisfied customers



Licensed mechanics

31,131 satisfied customers

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