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fowlers

check transmission and shift inhibit lights on

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I have a 2005 Itasca Meridian 39k, 350hp Cat with 3000mh Allison transmission.  We stopped along rural hwy for lunch, shut engine off. Went to restart and these lights came on, engine started but could not shift to drive.  shut engine off, restarted in 5 min w/o issues.  Stopped for night in small rural town in northeast Calif.  Engine started next morning but again had red warning lights and transmission would not engage.  New we are stuck, was told my freightliner that we would have to have towed in (175 miles), no fix w/o being put on computer. Does anyone have these issues and possible fix? 

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fowlers,

Welcome to the FMCA Forum.

Have you queried the transmission for diagnostic codes.

EASY from the driver's seat.  Instructions in your Allison owners manual or on Allison's website.

Another quick check if for chassis battery connections and voltage.

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Welcome!

Don't spend $$$ until after you do the free stuff first.  

What Brett don't know about Allison & CAT, is not worth knowing!

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Sorry for delay in answering, waiting for tow.  default code is 42 13, a short in the solenoid circuit.  We checked the battery terminals to see if tight.

called freightliner/Allison they said we most likely have a TCM?  we attempted to clear default code from shift pad w/o success. 

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No an Allison ECU is NOT an inexpensive fix.

But, first step is to verify that both 12 VDC hots to it and its ground are good (12+ VDC).

Without that, the ECU will be "stupid" and can throw random codes.  Only takes a few minutes to check and THE place to start.

If the Allison ECU is diagnosed as the issue, next step is to contact John-- he makes a living repairing them: https://www.transmissioninstruments.com/

Substantially less $$ than a new one.

Obviously, if a bad solenoid in the transmission, the above will not fix it.

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By chance did you check oil level at operating temperature? It's done by pushing the up and down arrows simultaneously  with tranny in neutral.

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1 hour ago, RayIN said:

By chance did you check oil level at operating temperature? It's done by pushing the up and down arrows simultaneously  with tranny in neutral.

Yup, and pushing them again brings you to the diagnostic code reader.

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yes I checked fluid levels as well as diagnostics. Codes showed 43-12 which was solenoid short circuit.  after 175 mile tow the problem ended up being the failure of the TCM (transmission computer module). Waiting for one to be freighted in (cost 3,900.00) wo we can get back on the road.  Freightliner dealer was not able to locate any short, and there was no problem with solenoid.  They used their service TCM, and were able to drive coach without problems.  So we ordered new module. 

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