Allison Electricle Problems

Discussion in 'Talkback' started by Allison Expert, Jun 13, 2011.

  1. Allison Expert

    Allison Expert New Member

    Hello to everyone...This seems to be a re-accuring question/problem I see in the differant forums. Do not shift light, shift pad not lighting up, trans shifts funny, etc, etc... So I thought I would post some tips and tricks for all to see that can hopefully answer alot of those questions. Not that any of us mind answering the questions, but this would give people a few things to try before getting frustrated and wanting to throw in the towel.

    First, the most common question is; shift pad lights up intermintantly?? All world transmissions use the same basic wiring whether it be WTEC II (two digit display, shift pad generally attached to ECU)
    or WTEC III (one digit display, ECU seperate) Almost any mechanic you talk to will call the trans computer something differant. ECU=Electronic Control Unit. TCM=Transmission Control Module. ECU is more common for WTECII and WTECIII. TCM is more common for 4TH Generation controls which is the newer electronics in most of the motorhomes 2007 and newer.

    With that being said, the power and ground wires for the two are the same. Wire 136 is your shift selector power, generally a pink or red wire, and wire 143 is your ground, generally a gray or black wire. Moste OEMs use some kind of VIM (Vehicle Interface Module) except FCC (Freightliner Custom Chassis) that is the hub for chassis, trans communication.

    Yes, this is alot of info, but hopefully this will help. You can also refer to the Allison web site which has alot of info that is very helpful. Again, we are always glad to answer questions, but hopefully this will help any of you with the technicle jargen...just remember, when something isn't working, go back to basics. Check your batteries and all connections. With the transmission, check fluid level and all connectors.

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