Problem diagnosing Allison 1000 problem

[classic60]

I have a 2003 Fleetwood Bounder with a Workhorse W22 chassis with an Allison 1000 transmission.

The coach has been suffering from a mysterious ailment for the last couple of years. (see "ghost engine stall" under Workhorse forum if interested) In essence, Redlands Truck Service has looked at it a couple of times and has been unable to find and correct the problem. Most recently, they concluded that it was most likely a transmission issue. It should be noted that no warning lights have ever come on in the dash.

To make a long story longer, the transmission shop, which has experience with Allison transmissions, had been unable to connect and extract any codes from the tranny for yet another mysterious reason. However, today I was told that the reason they were unable to connect is that the "OEM" did not wire the TCM to the OBD port under the dash..or at least that what I understood what the shop foreman told me. They are now in the process of running the wiring so that they may be able to extract any diagnostic codes which may be present.

Has anyone ever heard of this or encountered a similar situation?

[Dalsn1]

I would be skeptical of that answer, as the TCM and Ecm work together. When I had a trans warning light come on the Allison shop had no problem pulling the codes from the OBD port. Are you using an authorized Allison shop, they pull codes with a laptop.

Steve

[classic60]

I had been getting my information second hand over the phone but received more clarification when I went back to the shop. Bottom line, the problem the Allison shop has been having is retrieving codes. Using their laptop, they have been unsuccessful in communicating to the TCM through the ECM or however the info flows. They are stumped, even had their "top tech" take an unsuccessful crack at it. They concluded that at the moment, the origin of the problem is on the Workhorse side. Incidently, no transmission warning lights or other warning lights are present.

I went back to Redlands Truck Service, the Workhorse shop who looked at the coach originally, and tried to remedy the problem by replacing the NSBU module, now told me literally that they were not very good with that type of problem and recommended another Workhorse service center which is where it's at today.

[Dalsn1]

An Allison shop can remove the TCM and pull codes and test it on the bench. When I had my TCM flashed in Portland they couldn't find the correct connector has they don't work on many gas rigs. They removed the TCM and re flashed it. You might want to ask if this is an option.

Steve

[bruceh]

I had an Allison shop attempt to hook their computer to the OBDII port with no success. Later, I figured out that they had blown the fuse to the port.