Allison Transmission Problem

[HueyPilotVN]

I broke down on I-5 Saturday when my engine simple quit.  I coasted to the side and tried to restart the diesel engine.  I had a Trans Check light on and the engine would not crank at all.  My problem has been narrowed down to not having power to the shift console so that it can tell the engine computer that is is in neutral and ok to start the engine.  I did a search on here and found a couple that have had the same issue including Gary.  For them it was either the connector to the shift console, a fuse, or a loose wire.  I have checked the connector to the shift console, changed and checked the two 10 amp fuses located in the VIM (Vehicle Interface Module) located in the forward service bay below the drivers side and looked for any loose connections.  I have a 40 Country Coach with the Allison MH3000 transmission.  I was towed off the Interstate after 7 hours, long story, first tow truck was too small, it finally took one with four rear axles and $450.00 to do it.  I am back at the RV park by the Del Mar racetrack in Southern California with an appointment for a mobile Allison tech in the morning.  They have alread charged my credit card with $500 to show up.  If anyone has any input or ideas I would appreciate them.  MY hope is that the service tech will find the problem just like in the other post I read on here about the same problem but I would be happoer if I could find the loose wire and not have that expenxe.

This reminds me of a story about a farmer that had a Combine break down in the field.  The service tech used a small screwdriver and made a little adjustment and the conbine was fixed.  The farmer said "I could have done that".  The tech said "Yes, but you had to know how to do it".

It can be an expensive world we live in today.

 

[Ned]

First thing to do is get a CoachNet membership.  That would have saved you the $450 tow and much of that 7 hours.

 

[BillB3857]

Not sure about your setup but, sounds like the NSBU switch on the side of the transmission gave up. (Neutral, Start, BackUP)  A common problem for the Chevy/Duramax crowd. 

Here is a site that explains it for the DMAX crowd.  Yours may be similar.
http://www.n8fan.net/fopen/a2V5d29yZD1uYnN1K3JldmVyc2UrbGlnaHQrYWxsaXNvbiZsaW5rPWh0dHAlM0ElMkYlMkZ3d3cubWVyY2hhbnQtYXV0b21vdGl2ZS5jb20lMkZhbGxpc29ubnNidXN3aXRjaDIwMDEtMjAwNC5hc3B4

 

[HueyPilotVN]

First, You are correct about the Coach Net membership.  I usually do not break down.  IN about 750,000 miles of RV travel I think I have broke down only a few times in the last 30 years.  Will have to rethink that issue with the newer electronic controlled systems.

Thanks for the comment about the forward/nuetral/reverse switch.  That is the source of the problem in that it is not getting power or communication with the ECU, but mine is an electronic touch pad and not mechanical.  I have the Cummins diesel.  However your input is appreciated.

The tech just called to get any insight prior to his appointment in the morning.  I was hoping for a solution before his appointment but I am sure that his expertise will pay off.  I will post the results tomorrow and maybe save someone else some expense if they get the same situation.

 

[Michael Holden]

$450 divided by 750,000 in 30 years... I'd say you got the CoachNet-ers beat! No matter what it costs, your still ahead. Education is expensive these days so pay attention to everything that tech does and get your money's worth. Ya know how much it costs to go to Harvard these days? ...you're going receive some valuable instruction for relatively little money! Good luck, and I hope it's a simple fix.

 

[Gary RV_Wizard]

Mine was a loose wire near the Allison ECU. Wiring differs a bit from chassis to chassis, but basically there will be a couple of relays feeding power & signals to/from the Allison ECU, including the neutral sense, shifter console, ignition status, and so on. Most any of those wires could cause your problem, either at the relay or the ECU itself.


Nobody plans on breaking down - we do our best to avoid it. Coach Net is insurance in case plans go awry. You got off light with a $450 tow. $1000 plus is not uncommon. Economically, you are probably ahead paying for your own towing, but it sure is nice to be able to call for professional help that understands large RVs when the unexpected inevitably happens.

 

[Jeff]

CoachNet will also give you the option of being towed or sending a tech out if they think it is repairable on site. They paid for the service call plus an hour's labor for us last summer.

 

[HueyPilotVN]

Here is the results from the service call.  Overall I was very disappointed.  It cost me $500 to be told that it could be one or two different things.  First of all his laptop diagnostic tool could not get a connection with the service port, it started to connect but then did not.  After two and a half hours of trying to find the problem I was told that it might be the shift selector console or it might be the Electronic Control Unit.  the Selector console cost $850.00 and the ECU cost $2,850.00.  I asked if he could plug one in to find out which one was bad and I was told that he would have to drive back to the shop to get one and it would be another hour's fee ($120.00 and another $100 mileage (20 miles both ways at $2.50 a mile).  I asked him why he did not just bring one along since the problem was no power or signal from the shift selector. No answer.  My next step is to ask the fellow three RV sites down with an almost exact Country Coach to let me use his selector console to troubleshoot by substuition.  It is easy to remove and it simply has a circular connector and would not be in any danger of damaging it, (it is basically a bunch of switches like the armrest switches in a car). If it is damaged by trying it I would buy him another.  I will try that tonight to hopefully get a difinitive answer.  I went on EBay and found several of the Allison Selector switches, one for $40, one for $99 and one for $400 (new in the box).  I also called Colaw's Salvage and they are looking for one in thier boneyard.

That is my story and I am disappointed that I did not get a difinitive result, but I guess it was a learning experience as I was advised to get in the previous post.

 

[HueyPilotVN]

Here is an update with a great result.

I purchased a replacement shift selector console and plugged it in.  Same problem.  Frustrated, I called and spoke with Eric Reed, the service manager at Valley, (the Allison dealer in San Diego).  Eric stepped up and sent another tech with a Electronic Interface Module programmed for my coach to try substitution to see if the problem was the EIM.  I still had the same problem.  Oscar Salas, the tech started to troubleshoot and within a few minutes located the problem.  The nut on the bolt where the power comes thru a large cable in the electrical compartment was loose.  Problem solved without spending $3,000 for a new EIM.  Valley did not charge me for the follow up service call and they stood behind their work.  Now instead of complaining about the situation I am very happy to heap some praise on these guys.  Also today is my 63rd birthday, great birthday present....

 

[Kim (skyking4ar2) Bertram]

Since both of my coaches had/have that Allison transmission and shift pad, I am filing this information away for future use. Appreciate the detailed analysis.

It's great to hear your birthday present was exactly what you needed!  8)

 

[Kevin Means]

It's always nice to hear when a company stands behind their work. Glad to hear you're back in business without too much out of pocket (and happy birthday!)

Kev