Transmission Problem / Broken down...

[Mike Stuart]

I have what looks to be a transmission problem.
02 Marquis C-12/Allison transmission
While driving slowly (30mph), I received a red Check Transmission light.  At the same time the speedometer went stop to stop and then died at zero.  Also, I didn't have any lights on my transmission control.  I pulled off the road and parked.  At this point the engine is operating normally, just no indication on the transmission.  I did not attempt to shift to a gear; rather just selected Neutral and shut the engine down.  The engine will not start now and is not receiving any information from the transmission.  I have X/X on the Silverleaf in place of gear selected / actual indication.  Also no data on transmission oil temp.  A visual check of engine and transmission shows nothing out of the ordinary.  No fluids leaking, etc.

Any ideas on what may be going on?

Thanks in advance!

[Roy Warren Co-Admin]

When I couldn't start my coach and had no transmission lights, I called Allison.  It cost $75 and they replaced a small 5 amp fuse in a box in the electric bay for the Allison.  You might start there.  An expensive fuse lesson.
Roy Warren

[Mike Stuart]

Thanks Roy.  Good idea.  I assume you meant the fuses in my main fuse panel.
I checked that fuse and all the others in there.  All are ok.
So my problem must be elsewhere.

[Bill Lampkin]

I think what Roy means is that there should be an Allison transmission module in your front run bay.

[David T. Richelderfer]

The Allison module in our coach is directly under the transmission keypad shifter.  Access to it is through the vertical side panel by the pilot's left leg when sitting in the pilot's seat.  As I recall, the module is a black plastic box measuring approximately 5x7x2 inches.  The black box opens like a clamshell after loosening several screws.  Inside the box, there are two auto style fuses.

The transmission MUST report an "N" (neutral) gear selection on the keypad before the engine will be allowed to start.

[Eric Maclean Co-Admin]

Mike
 on most allison automatic installations there is a fuse holder in the battery bay which contains a 10 Amp fuse which supplies
the main power source for the transmission control it sounds like it may be blown
with out the neutral signal from the TCM the engines ECU will not be able to verify neutral saftey and will not send a crank signal to the starter.
there are also fuses in the Allison relay box (left front electrical locker) which contains fuses for the shifter and some of the TCM outputs
as well but if the main transmission feed fuse (battery bay) is blown none of those fuses will be powered.
good luck
Eric

[Roy Warren Co-Admin]

Mike is correct.  On my coach, the black box is mounted on the back wall of the electric bay.  Check the fuses in there.  Very similar coach to yours, 2005 PT Vicksburg Model.
Roy Warren

[Mike Stuart]

Many thanks to all that posted with suggestions.  We checked all fuses (yes found the ones below the shifter in the clamshell box; 10A) and all were good.  Turns out the Electronic Transmission Control was the culprit, and an expensive one at that.  It was kaput.  We were able to get superb service out of Jacksonville from Progressive Power Products, Allison Experts.  They diagnosed our issue quickly and got us on the road.  FYI, new ETC's are not readily available and they installed a loaner programmed to our specification.  When the new unit comes in they will switch it out with their loaner.  They got us on the road and on our way.

Again thanks to all for your input!