Transmission warning light,, Why is it on?

gyoder · March 21, 2013, 12:44:02 PM

I am working on a 1992 Prevost XL40 with a 8V92TA

for a friend. Someone ahead of me was putting new batteries on this coach and put one battery on backwards and gave the coach a reverse spike. It got the DDEC II ECM but after getting it rebuilt I got it started but I have a "check Transmission" light on in the dash and in my shift pad there is a red section flashing "do not shift" and a neutral light on. Where do I start looking??

I took the ATEC ECU off and the shift board, and sent it to the computer shop and they said they are fine.

luvrbus · March 21, 2013, 01:00:24 PM

Try holding down the 2 arrows simultaneous with the key on that will flash the codes then hold the mode down till you hear a tone in a few second hold down for a few more seconds and the codes are cleared,remember the AETC took the same shot as your DDEC you may have bigger problems

gyoder · March 21, 2013, 07:12:16 PM

Quote from: luvrbus on March 21, 2013, 01:00:24 PM
Try holding down the 2 arrows simultaneous with the key on that will flash the codes then hold the mode down till you hear a tone in a few second hold down for a few more seconds and the codes are cleared,remember the AETC took the same shot as your DDEC you may have bigger problems

thanks I will do, and get back with you

gyoder · March 22, 2013, 01:39:43 PM

who takes the credit for the ATEC system? its not Prevost, Country Coach, Allison, or Detroit,
I have 1992 Prevost XL with a transmission light on will not go into gear, and I can't find out how to get the codes out out this thing. I have tried to use the shift pad but no luck.

luvrbus · March 22, 2013, 02:24:38 PM

Quote from: gyoder on March 22, 2013, 01:39:43 PM
who takes the credit for the ATEC system? its not Prevost, Country Coach, Allison, or Detroit,
I have 1992 Prevost XL with a transmission light on will not go into gear, and I can't find out how to get the codes out out this thing. I have tried to use the shift pad but no luck.

luvrbus · March 22, 2013, 02:26:26 PM

Hold the mode button till you hear a tone it should bring the codes up,Allison takes the credit what generation is your ATEC or what transmission model if it is a 755 you are on your own lol and you have my deepest condolences

FWIW you can down load a manual from Allison for 60 bucks it maybe money well spent they can be a night mare but yours sounds like a ground problem

good luck

gyoder · March 22, 2013, 06:59:53 PM

Quote from: luvrbus on March 22, 2013, 02:26:26 PM
Hold the mode button till you hear a tone it should bring the codes up,Allison takes the credit what generation is your ATEC or what transmission model if it is a 755 you are on your own lol and you have my deepest condolences

FWIW you can down load a manual from Allison for 60 bucks it maybe money well spent they can be a night mare but yours sounds like a ground problem

good luck

The shift pad has one empty little square that blinks and says "don't shift" in it, I have held it down and nothing happens,
it is a HT 755CR, I called Allison and they said they are only responsible for the wiring inside of the transmission, all the Allison people don't have any software to pull the codes out of this old a system. The Allison guy told me it was a engine issue that the ATEC reads the motor ECM. I just had the Engine ECM rebuilt and all is well there.

It is nosed into a storage building and no way to get a wrecker to the front of it, I have to crank this beast right where it sets somehow.

Do you know of anyone who has a reader to pull the codes out of this model of setup?

robertglines1 · March 22, 2013, 07:14:47 PM

Other possibilities: Slides must be in. (if equipped) Maybe foot on brake(some later model) had feature. Engine idle to high. Also trans oil temp to low(-50F) switch faulty or wire broken. Remote uncommon things. Bob

robertglines1 · March 22, 2013, 07:44:23 PM

Is the dash tach working? The engine ECM has to talk to the trans Ecm for the trans to work. Bob

gyoder · March 22, 2013, 07:54:23 PM

Quote from: robertglines1 on March 22, 2013, 07:44:23 PM
Is the dash tach working? The engine ECM has to talk to the trans Ecm for the trans to work. Bob

yes the tach works good

luvrbus · March 22, 2013, 07:57:18 PM

Wish I could help I have D.O.C that will read the WTEC 2 and up but not the 755 I have been told that anything that will read the 4L60 and 4L65 GM transmission like a OBD11 will read a 755 I never tried it so I don't know if true or not.

If you give Kim or Bobby a call @ Global Transmission in Tuscon Az one of those guys can answer your question on your 755 or if anybody here knows how to reach Bob Ware he can help you also

good luck

gyoder · March 22, 2013, 07:58:25 PM

Quote from: robertglines1 on March 22, 2013, 07:14:47 PM
Other possibilities: Slides must be in. (if equipped) Maybe foot on brake(some later model) had feature. Engine idle to high. Also trans oil temp to low(-50F) switch faulty or wire broken. Remote uncommon things. Bob

it has no slides, but I never thought of having my foot on the brake, I always take it off of high Idle and its idling at 550/600, I give these things a try
this all started when a guy put a battery on and crossed the leads, it was doing just fine till that happened,

gyoder · March 22, 2013, 08:00:31 PM

Quote from: luvrbus on March 22, 2013, 07:57:18 PM
Wish I could help I have D.O.C that will read the WTEC 2 and up but not the 755 I have been told that anything that will read the 4L60 and 4L65 GM transmission like a OBD11 will read a 755 I never tried it so I don't know if true or not.

If you give Kim or Bobby a call @ Global Transmission in Tuscon Az one of those guys can answer your question on your 755 or if anybody here knows how to reach Bob Ware he can help you also

good luck

thanks I will contact them

gyoder · March 25, 2013, 12:46:48 PM

Can a ATEC / Allison transmission computer [ ECU ] be diagnosed/checked out if it is off of the coach? I pulled this ECU to have it checked out and the company said it was good, but several Allison people tell me it must be on the coach using a break out box to properly diagnosed.

akroyaleagle · March 25, 2013, 02:31:10 PM

I don't know much about electronics but if you didn't let the smoke out, I'd think it is probably not damaged much.

It is hard to believe the runaround you are getting.

Since this problem started with battery work, have you rechecked all the cables and wires and ensured they are connected/grounded correctly?

Is/was there a fusible link somewhere upstream of the transmission.