I just wanted to give a heads up to anyone traveling in the Ft. Wayne, Indiana area, who might need service on their Allison Transmission. I won't bore you with the details but my recent experience with the local authorized Allison Service Center, Clark Power, was disappointing, to say the least. I'm not sure how they train their staff at other locations but the ones in Ft. Wayne are far from being $140 per hour professional Techs. FYI: They are also a DD authorized center and they couldn't even give me a DDEC read out. Hope all is well with all the Gurus.
UPDATE: I wrote a letter to both Allison and Detroit explaining my experience and disappointment. I received a call from Allisons Reg. Mgr and will be meeting him at the Ft. Wayne Service center on 6-21 where he tells me they will correct the problem. I'll let you know the results. A man called from Detroit Diesel but could only confirm that not all service centers have up to date programs for DDEC readouts.
I had my appointment with the Allison techs Thursday, June 21, at Clarke in Ft. Wayne.I'm going to describe the experience and see what kind of thoughts I get from my fellow Gurus before I send another letter to Allison. The 2 techs arrived at the appointed time, said hello and they put the coach in a bay. I asked if I could come and be of some assistance and got a very curt No, from the man in charge. I sat in the waiting room for a little over 3 hours and could hear when they started the engine, left it run for a while and shut it down. This happened numerous times before they finally brought it back outside, came in and said it was fixed. The culprit, according to the lead tech, was a relay in the Allison brain. They gave me the defective part so I went in the coach and was totally relieved to see the check transmission light was finally off. They said there was no charge, I said Thank You and went on my way. When I arrived at our storage building, I tried to put the fast idle on, while I went inside to open up and move my car. The fast Idle was dead. Then, when I left the Coach to open up, the step was out and inoperative. Both of those worked that morning as they always have. Now I'm a little suspicious so I pulled the Ck Tran lite and ran a test. The bulb was good so I checked the wires coming to the lite and there is no power. I forgot to plug it in so I went back the following morning. Guess what, both the fast idle and step were working again. Still no power to the lite. Now I'm really suspicious and disappointed. Any thoughts will definitely be appreciated.
I have had flaky issues with both fast idle and the step so I don’t know if there is a connection to the Allison work.
If I interpret your post correctly you ran an check transmission test which should have caused the transmission light to flash. It didn’t. The bulb is confirmed good. But no power to the bulb when the test is activated.
If that is true then I would call the shop and speak to the service manager. I would ask “ what should happen when I run the test transmission light?” Of course it is supposed to blink . I would calmly explain that you were just in for service to clear a transmission code and you don’t understand why the light is now non functional. Then I would say that before I made a perhaps erroneous conclusion would he like an opportunity to look at the coach again?
I know it’s a bit of a trip .....
Thanks Richard. I'm not real educated when it comes to these systems but, it appears to me that something triggered the non-working step and fast idle features and I'm thinking that after the coach was shut down for some time these systems "reset" themselves. I did not run the test transmission lite feature because I thought that the check transmission lite would come on each time you turned the ignition on as a type of bulb check feature, like the other dash warning lites and then go out before starting the engine. I will try that today. Hopefully I was mistaken and it is fixed.
The service manager is out of the picture as I'm dealing with the Allison home office in Indy. They sent the techs to fix the issue. I want to have as much good info before I talk to Indy again. Thank You for your input.
According to the Allison manual for the HT and MT series electronic transmissions, the "check trans" light has 12vdc on one terminal and the ground side is connected to ground through a relay triggered by the ECU grounding the coil of that relay. The power to the coil comes from 12vdc supplied through an oil pressure switch on the engine. The relay is held open when there is both oil pressure and the ECU providing ground (neither the "check trans" switch nor ECU sensed anomalies causing the coil ground to open).
On my 93 coach the relay is the 3rd from the top in a stack of relays in the compartment containing the Allison ECU.
You said there was no power to the "check trans" bulb. It is designed to always have power and only the ground side is controlled to turn it off/on. In my 93 coach that power comes from a circuit that supplies power to other things in the dash.
There is a relay that sends the "fast idle" signal to the engine ECU by grounding the signal wire. On my coach this relay is mounted in the front panels by the copilot's feet. The "fast idle" switch uses 12vdc to turn on the "fast idle".
The idle issue and the step issue seemed to appear and disappear at the same time. I suspect that a loss of power to the "fast idle" switch and the step occurred at the same time. I don't know enough about the wiring to offer a suggestion for how that could occur and then self correct, maybe it's just magic.
Thanks Jon. Does your check trans lite come on when you turn the ignition on?
Yes, the light comes on ding startup, just like the "check engine" light for a few seconds.
That's what I thought, mine does not. I pulled the lite out to check it. I don't know if putting the wires on the wrong terminals would make a difference, but I'm going to reverse them tomorrow and see if it comes on then. I really don't want to find that they may have deliberately eliminated the power to make me think the problem is solved, but it has entered my mind.
I've checked the ck trans lite every way I know how and the lite does not come on with the key on, off nor with using the toggle switch although the bulb is good. I'm really getting suspicious. These were FACTORY Techs. I can"t believe they would drive all the way from Indianapolis to Ft. Wayne, spend 3 hours looking for the problem, think they found it, replace the "bad" relay and not check to see if it operates properly. What in the world did they expect it to do?
Can anyone think of anything else that maybe I've overlooked, before I write their Mgr. and relay my experience. I really want to sell the Coach but would not feel comfortable with this issue unresolved.
They also must have used my manual, which was laying on the sofa, and is now gone.