# 1997 Holiday Rambler Imperial "Do Not Shift" issue



## BamaCowboy (Sep 19, 2020)

Went out today to move my RV and when I cranked the unit the Allison Transmission Console started blinking On and Off, also my tail lights in the rear are blinking as though the Flashers are on. Plus the Dash Board displays the DO NOT Shift Light...

Any help on cause or troubleshooting would be greatly appreciated !!!


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## BamaCowboy (Sep 22, 2020)

More Info.  when I cranked the unit the Allison Transmission Console started blinking On and Off, also my tail lights in the rear are blinking as though the Flashers are on. Plus the Dash Board displays the DO NOT Shift Light... I noticed the RPM jumping up and down in the same rhythm as the blinking. If I walk outside and and listen at the rear the engine is huffing at the same rhythm. if you hold you hands behind the exhaust you can fell the pressure of the output change at the same pace. When Idling
If you give it gas The RPM and Pressure continues to fluctuate at the same rhythm....


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## RUn2it (Sep 23, 2020)

Sounds like it could be the relay that controls your exhaust brake and also connects to your trans ecu, just guessing and if you have an exhaust brake.


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## BamaCowboy (Sep 23, 2020)

RUn2it said:


> Sounds like it could be the relay that controls your exhaust brake and also connects to your trans ecu, just guessing and if you have an exhaust brake.


Yes it has an Exhaust brake... ..Any idea where this would be or how I might Identify its location/name


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## RUn2it (Oct 2, 2020)

I added an exhaust brake to my 94 HR Endevor and wanted total control independent of the 3060 ECU but your brake relay or what ever they come with is probably in a plastic box 8-10 inches square on the inside firewall behind brake pedal, maybe 6-8 small bolts on the lid, remove lid and get it started, idling and if it's still loading and unloading feel the relays to see if 1 is clicking, if so you found THE relay, the hard part will be determining the source of the signal to the relay. Years back returning from a race I stopped at state line, Nevada/California and when I started to leave the engine started but the do not shift dash warning was flashing and no forward or reverse gears. I removed and opened the keypad and control ECU and I believe there is 5 separate boards, and a few electrolytic capacitors, old school nowdays, they look like little Coors light cans about the diameter of a pencil and around 1/2 in +/- tall, 2 wires. They have electrolytic fluid in them when new but with age they get sensitive to cold temps. I positioned the boards on the floor for access but still connected and 1 by one took a wooden match, lit it till burning well, blew it out and touched it to a capacitor and quickly started engine, finally after 2-3 caps the do not shift light wasn't on. Fine, know it has a bad cap but luckily once started and with heater on I drove home without incident. I repeated the high tech troubleshooting the next day to see how many caps were bad, 1 at a time, but ambient heat was high enough and the problem wouldn't repeat so I did the reverse, 1 at a time, got frost from the freezer in a baggie, touch each 1 and start engine. Sure enough the do not shift light would come on, then "match" it and it would go off. Found an electronics store that had them in the capacitance range I needed and replaced them and was good for 5-6 years. The next problem was not repairable but found a core module online and sent it to the guy in Texas, John at ???? instruments, a search will find him, $500.00 and still working no problems. It's either John or a RV junkyard but it's still a used 1 and can croak at anytime, good luck on price for a new one, was $3500.00 back then, who knows now. John will make it right as long as a board isn't burnt. Sorry, It's a term paper post, I know, but it's everything that's relevant that I can remember. 2 signs of aging, 1 is short term memory loss and I forget what the other 1 is.... GOOD LUCK, remember, humans built the dang thing and you're human and can get it going with some head scratching. Lee


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## BamaCowboy (Oct 27, 2020)

More detailed trouble shooting Info...  
I have a 1998 Holiday Rambler Imperial with a Cummins Engine and an Allison Transmission. I am experiencing an issue than no one seems to be able to explain or diagnosis.

About a 4 months ago I was doing my annual touchup / maintenance and had moved my RV to my main Driveway to prepare for several upcoming trips. All of my maintenance this time was non mechanical mostly cosmetic. However, when I went to pack and begin to relocate for my trip I cranked the engine and let it idle for about 20 minutes. Shortly after words I began hearing a clicking sound like a blinker. I noticed my Electronic shift panel was blinking to the same rhythm and my Exhaust brake was huffing a the same pace. And MY Dash displayed “DO NOT Shift” . And my RPM gauge was jumping up and down a couple of 100 with each click.

I managed to turn of the Exhaust brake and the huffing stopped. However, I continued to trouble shoot with no luck. A few days later I went ot crank and trouble shoot again. This time it did not blink or give me the “DO NOT Shift” for about 20 minutes then it started again. And as of today I can not get it to stop again.



Diagnosing :

I have checked the Error code process and ONLY can get it to give me a LO Trans Oil code. But it will not give me any more codes no matter what I try. (Had a local Allison Mechanic verify)

I checked the Trans Oil Level at the dipstick “NOT LOW”

Traced the clicking down to an Allision Transmission Relay box under my Dash Written on the Description is “P/N 29509886 12 volt 6 relay”. The Relay that is clicking is located in the upper middle of the box. The relay location is Marked “SFO2”. If I pull the relay it stops the clicking but the rest of the blinking conditions continue. The Allison Tech wanted me to ask if this might be the entire board causing this issue since the conditions do not stop when relay is pulled.



ANY HELP would be appreciated, As you can tell by my email, I am no Transmission expert, but I am mechanical savvy if I can get enough details.


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## RUn2it (Nov 4, 2020)

Just taking a stab at it, disconnect all connections to the trans ECU under shift pad and connection to the relay box and do what needs to be done to start engine, may have to jumper from battery to the fuel shut off solenoid next to fuel injection pump or manually pull up plunger into solenoid and duct tape or clothes hanger wire it in the up (run) position, and may have to jump starter solenoid, if your exhaust brake is stuck closed you'll hear it, if not the engine should idle fine. Have to start somewhere, process of elimination. just by the way you describe the sounds it sounds like something triggers the ex brake relay energizing the brake compressor but it's stuck closed and the compressor pressure switch cycles it off but the relay starts the whole process again. Trying to diagnose from someones description of the sounds is only a notch above pin the tail on the donkey method, but it's a mechanical engine except for the ex brake , starter and fuel shut-off. You should get in touch with the guy in Texas, I think his name is Paul and Transmission specialist.... search until you find it, he can probably tell you what it is.


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## BamaCowboy (Apr 13, 2021)

Update on this issue...It was the ECU unit underneath the steering column. It has 6 relays and appears to have had some type of heat/cold/humidity issue. We managed to get it to move one dry cool evening but the next day the issue returned. We replaced the unit with a salvage ECU and the issue went away.. Thanks to everyone for the help


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