Coach won't shift into gear

[BillhymerMD]

I wonder if it could be the shifter control module. Our '92 Country Coach with Allison HT755CR transmission all of a sudden has decided not to shift into any gear. It has a selector module that does not allow for one to see any error codes...its a classic style. The "do not shift" is not illuminated. The emergency brake and been pushed and pulled a dozen times, the brake is depressed and engine and tranny warm and she will not shift out of Neutral. The neutral button is illuminated. The Drive and Reverse have been pushed in all manner of way with pens and fingers with no luck. Tranny fluid is fine. Does anyone have any experience with this?

[garyde]

The last time I saw this thread, it was time to replace the pad. There was some luck in using the end of a pencil eraser pressing hard which got them going. If you can look at the wire cable connection, un plug it and plug it back in, that might re boot it.

[merle&louise]

If it is on high idle that will prevent engaging D or R!:confused:

[BillhymerMD]

Its not on high idle and has always worked perfectly before this. Outside temp is in the 70s - 80s. Of course I've restarted the coach several times. Ill try removing the module and then reconnecting it and see if that helps.

[jimblu]

Same transmission, same problem, although it would sometimes shift if you held the button down with a pencil for a few seconds. A rebuilt unit from http://www.gendieselect.com/ fixed it right up. Can't find the invoice but it was reasonable compared to Prevost.

[AmeriStar]

You might try shutting the bus power off with the main battery disconnect for a couple of minutes and then trying to shift after starting.
Its rare, but sometimes a 'reboot' of the ecm will fix the problem.

[CAPT MOGUL & Sandy]

Michael, did you solve your problem? The same happened to Ed & I one time when we just pulled on to the side of the road and put her in neutral. We still had the engine running and then got ready to travel again, it wouldn't go out of neutral. We shut the engine down and then restarted & had no problem after that.
As you see, I am just the wife here, the afternoon driver(relax time for Ed), but always asking questions to learn. Would the"over ride" button help any?
Sandy

[Loc]

Michael,

You should have a ATEC switch in the compartment below the driver's seat. If you switch the ATEC switch and then turn the key on you should get a series of flashes on the transmission telltale light on the dash. The Prevost manual has a page with codes for the ATEC flashes. This may help you determine the problem. If you get no codes then I would suspect the keypad. Allison Transmission has a US toll free service number 800.524.2303 that you may want to give a call. Good luck. I had a speed sensor go out in the transmission years ago and the bus would not shift. However, the ATEC switch gave me the code to determine it was the speed sensor. Good luck.

[Coach Pro LLC]

Here is something worth a try that will not take much time and might (might) solve the problem or at least help in further diagnosis.

Ignition on, engine not running.

Press Neutral / drive / reverse 3 times: N D R N D R N D R

Depnding on the the type of code, this may clear it.

It is the sequence from Detroit to clear some codes....

Good Luck,

Pat Sprenger
COach Pro LLC

[BillhymerMD]

Thanks for the great info. I tried turning the coach off and on a number of times...I even disconnected and reconnected the batteries without success. I also tried the N/D/R sequence 3 times and more without success. When I flipped the ATEC switch in the steering compartment below the drivers seat I got 2 quick flashes followed by 3 quick flashes on the "Check TRAN" light cycling over and over again...error code 23. In the Prevost manual that corresponds to a Shift Selector (Primary) problem. Thus, I guess I need to find a new or remanufactured shift selector. I had one quote already of $3,800. I passed. I'll keep searching till I find one that is a bit more reasonably priced. You guys have been great, Mike

Just spoke with the gentleman at http://www.gendieselect.com/ and he told me he would charge me $220.00 to send my unit in and have him "remanufacture" it or rebuild it such that it has a new keypad and works perfectly. I think Ill try that since jimblu seems to have had success with him. Thanks Jimblu!

[AmeriStar]

This is an old thread, but we had a bus stop in our shop yeaterday with this same problem in a b500 transmission, '94 vintage.
Our tech simply removed the Allison transmission shift contol module and carefully opened the box to expose the circuit board and pushbutton pad.
Using a Qtip dipped in either, simply clean both the board contacts and the magnetic points in the keypad side.
Reassemble carefully and plug back in, works like new. A new module lists for 2900.00, so if you experience this, don't be too hasty in purchasing new.

[JIM KELLER]

I love how the support pours in when a member needs help !

[dale farley]

The Qtip and ether fix sounds much better than the $2900 fix. One of those tips that validates what a great deal the $100 membership is.

[Dick in Wisconsin]

I don't even have a coach yet and feel very strongly I've gotten more than my money's worth!