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Do not shift lite
Stuck in a truck stop and the transmission will not shift
engine run fine
Ht755 5 speed Allison on a 91 XML mh chassis
Anyone know how to reset or why it is doing this
Allison no help prevost action service working on finding more info
Is the a reset
Fluid level ok
Allison says it is inhibit shift code that do not display readable codes
Greg
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13 Replies
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Mine wouldn’t shift into gear after a 300 mile trip. Killed engine and worked/shifted after. Jon posted one thing could be the wiring harness and corrosion at transmission plug.
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yes if I had my stands I would work on that connector
right now SOL and taking up a fueling island, no movement
Greg
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Greg, as I posted previously our problem was corrosion in the connector which caused the transmission to think it was below 20 degrees. That in turn wouldn’t allow shifting. I suspect you are unlikely to have the exact same false reading, but your best bet is to start by reading the transmission code. You likely can flash the codes so get help from Prevost on houw to do that. On my coach I could throw a switch and then jumper between two reader pins to get the codes but my 87 is unlikely to be the same as your coach.
The 755 transmission has several “do not shift” causes and it could be a bad connector but it could also be as simple as the coach thinks the engine is in high idle.
Without reading the code it is only speculation.
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Greg, I don’t have the Allison manual, but this is from the Country Coach manual I got with my 1990 XL which had the same transmission. Hope this helps.
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Allison tech told me that there are no codes for a “do not shift” lite. The reason for the lite could be high RPMs or anything that the buyer of the coach wanted to trip the warning.
I did after many phone calls get someone from Allison to tell me to disconnect the battery terminals and wait for 5 minutes. I did that and the warning light was turned off and I was able to put into gear and drive away. The battery disconnect must have erased the memory.
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Here is the code list:
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Thanks Bryan
By the way where is this “trans lite”?
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Greg, that is referring to the check trans light, which on my bus was adjacent to the check engine light on the dash.
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Greg,
With all due respect to the guy that told you there are no codes for the do not shift light (on the transmission pad) that is not true. When I had the problem with my connector and corrosion in it the code was a low temperature.
The initial thinking was the temperature sensor was bad. It turned out the plug had corrosion which screwed up the signals to the transmission brain. I agree a high RPM which keeps you from shifting into gear is not going to throw a code, but it also is not going to light your do not shift annunciator.
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I was very impressed with the lack of knowledge from the hot lines. But the prevost guy was no the line with me a long time as I tried different things to get it gear. I should call him back and tell him what I did to get it in gear. Problem is 23 year old technology and a lot of new techs, I am sure if this was a newer coach I would have been on the road long before. Got to keep this website going so we can help each other. Two calls to a DD/allison dealer before I got the battery disconnect advise. No one knew that you had to jump the two connectors to get ATEC codes to appear.
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Anyone that has ever called Direct TV will clearly understand the techs that answer the phone are reading instructions back to you. They have no clue. I’m not saying Allison, or Detroit or Prevost hot line folks are anywhere near as bad as the telephone answerers at Direct TV, but my guess is they are not mechanics.
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I recently had the do not shift light come on. In my case, it turned out one of the selenoids was bad. Mechanic told me that when I see the do not shift light come on that was what it meant. You do not shift the transmission when that light is on. Get off the road to a safe place. In my manuals it did state that to reset, all I needed to do was to turn off the engine and restart. I also had this issue happen after fueling and moving forward. The light was on and I couldn’t move after getting my receipt. My wife is a big believer of rebooting things when they don’t work right. In this case, “rebooting” was restarting the engine. I was able to get moved out of the line at the fuel dock.
Since my transmission is so old, it does not retain the codes. The mechanic dropped the pan and was touching each of the selenoids when he found one that went off line. Replaced that selenoid and all was fine on our next trip.
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Rod I was also getting fuel. but I started and stop the engine many time and still no reboot. I had to disconnect the batteries for 5 minutes to reboot. I have since tried to retrieve the codes but I get the same codes 16, 43, 44, 58. I have but the Ddec switch in test and I get the same codes from the CEL. I did the same with the ATEC and got the same codes, both switches in test mode and got the same codes, Did the same thing with a jumper in the the far right connetor slot and got the same codes. Never saw a check transmission light.
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