Good Morning,
Retarder Joy stick is all the way forward, retarder switch is off, foot on accelerator traveling normal. Foot off accelerator, transmission attempts to downshift to 2. I must keep some pressure on accelerator to coast. Very hard to do in city driving. I removed large connector from Joystick and reconnected did not see anything loose or out of ordinary in console next to my left leg. Normal operation has been that with the joy stick all the way forward, and retarder switch off, when I would remove foot from accelerator coach would coast until I touched brake or switched retarder on. This started just before we left from our two month trip. Guess I should have done something about it earlier but I adjusted my driving to compensate. Using the cruise control as much as possible helped and learning to keep just enough pressure on accelerator to keep transmission from trying to downshift. I have done a ton of searching and reading the forum but have not been able to find this issue discussed. So I am asking for help now.
Is shift selector pad in normal or economy? My will shift more frequently in normal. Economy seems to hold it up a bit both up shifting and down.
Scott
If the on/off switch and the lever were installed to work in the opposite directon from what we are used to, that would produce your situation. You might turn the switch the opposite way and pull the lever all the way back and see what happens. Just a thought but the down shift to second says the retarder is ON and the lever is at max retard.
The on/off switch works normally. Lights up red when on and active. 'retarder works normally when switch is on and lever is moved back to one two or three. Retarder heats up normally in use. Coach just will not coast unless I select neutral.
Normal and Economy work normally. as Brett Wolfe has so eloquently described. Symptom occurs in both modes.
Does your retarder temp fluctuate normally as you accelerate and decelerate or stay hot? Wonder if the solenoid on the accumulator could be sticking.
Herb, you are welcome to come see me on east side of Houston. I have an Allison Guru that will solve it
We drove over the Smokies twice back and forth. Retarder works normally, heating up while active and on, cooling down when I turn the switch off. As Rudy says it acts like the switch is on.
Thanks Rudy, I am in Houston until I return to coach Friday. I may very well do that. I will call you.
On my coach the retarder doesn't have anything to do with the trans shifting to 2. I wonder if
they changed that in the newer coaches. When I put the Jake brake in I found the wire under the
dash so I could hook it up to a floor switch so I could use it for the Jake. It was # 9 wire in the
trans computer.
Does your display that you are using to read retarder temperature also show gear selected and actual gear position? Would be curious if when your in fifth gear it is requesting 2nd gear on display. This is not displayed on your shift panel. I don't believe this is related to your retarder in any way.
I have a Silverleaf that shows gear selected and gear attained and mode 1 (power) or 2 (economy). When I let off of the accelerator the display shows 2 5 or 6 as I continue to slow the second number or attained continues to drop until I stop.
Sounds like it is actively seeking second gear. Mine will do that if I have the normal mode selected but doesn't in economy. Sounds like the shift programming has changed. Drivable but yes annoying. Rudy's tech should be able to resolve
Poor Boy Glass Dash
https://www.foreforums.com/index.php?action=dlattach;sa=tmpattach;attach=post_tmp_6845_bb22089d3a9387cf554526f7b3341947;topic=45182
On the way back to Livingston, This happened twice. Set cruise control to 62 mph and Mode 2 and after a time, the transmission acted like I turned the key off. Cruise control went off and mode went to 1. I reset cruise to 62 and clicked Mode 2. After a time it happened again. I reset cruise to 59 and Mode 2 and it never happened again for the next few hundred miles. Possibly related, but do not know. Loose or corroded ground? Some where?
That's the most likely culprit IMO. I would start there.
Update on coasting issue. Got Lewis Large (On rec. from Rudy) to come take a look. Lewis only works in the evening and night. So he came and put his computer on my data port after disconnecting my Silverleaf. Determined that Retarder and switch was working normally. After hearing my symptoms he decided that he needed to check a solenoid that was in the valve body. He took all of that apart and installed solenoid even though upon disassembly determined that the old solenoid was working ok at the time. New gaskets and salvaged most of fluid to return to transmission. Lewis had a pump to restore fluid, but the batteries were down and needed some D cells which neither of us had. So he buttoned things up an left for two days. While he was gone I got some D cells and pumped the fluid back into transmission. When he returned, he checked some pressures and removed gauges from transmission. We went for a test drive, and no improvement. Could not tell for sure but it seemed to shift smoother, but still would not coast. It did not seem to be as much of a problem as it was on my trip. However I figured out that the coasting problem is much more obvious when I am pulling my Jeep Grand Cherokee at 5K lbs. No problem towing it, just hat when I want to coast it brakes much harder with Jeep in tow than without. Makes sense when you think about it. At the point Lewis left and planned to bring another transmission ECU to try. Upon his third trip to my coach, Lewis replaced the ECU with a rebuilt one. We took another test drive and the transmission would still not coast. Lewis did some more checking and noted that the Engine ECU told him that the Jake brake was on. Of course I do not have a Jake brake, I have a retarder system which is working properly. The light comes on the switch and Joystick adds increasing retardation as moved rearward. Lewis felt that he was at the end of his ability to find the problem, except for the Jake brake indication which would require another skill set to run down. So he contacted Jason Cantrell at Mid Coast Engine Transmission Inc in Houston TX. He suggested that I bring my coach in to him. He felt like he could solve the issue. One thing we surmised is that Foretravel put a Jake Brake signal wire in the ECU harness that may have rubbed against a clamp or brace and shorted out to ground which maybe sending the transmission a signal to not coast because it expected a Jake brake to be engaged.
At this point Lewis Large of Expert Transmission (Allison Trash Trucks) gracious has not charged me a penny for 3 trips and much work. He refused to accept payment for not solving my problem. He does agree I have a problem so he is sending me another shop.
We are currently at Gone Fishing RV Resort and upon our return to Livingston Monday, I have spoken to Jason and we have a tentative appointment with Mid Coast for Tuesday AM. The search for a solution goes on.....stay tuned.
With the computer saying the Jake brake is on that would tell the transmission to shift down to
what ever gear the computer is programed to shift to and from your description I would say it is
second gear. When I was hooking up the Jake I installed, I found the wire under the dash that
would do that. It will only activate with no throttle and if cruise is on it won't come until I get the
cruise off or I'm 5 miles an hour above the speed I set the cruise at which was set by Cummins.
I believe that the wire is grounded for it to call for 2nd gear. I hope this helps.
That make perfect sense seeking to downshift. Workaround may be pulling that wire were in goes into ECU
Yes, that confirms what I suspected. Now to just find that wire and disable it or find the how it has suddenly found a ground. Maybe the engine wiring diagram will have a PIN number from the ECU plug. Thanks guys
Here is picture of the Allison wire/connector chart. The downshift wire is #11. I was wrong when
I said # 9 in a previous post. The picture is where I connected to the same wire to go to the switch
I put in. I hope this legible as I couldn't figure out how to scan it to this computer.
I will try later to figure out how to send the scanned copy as the copy I sent isn't very clear.
The yellow wire to yellow wire is the connection I made.
I can read it though thanks
I am trying again
That's better. Click on it twice
Update on coasting problem. I drove the coach to Mid Coast Engine and Transmission in Houston TX. The first day we spent several hours driving with technician and his laptop connected to my round data port. He and his supervisor determined that I was having an issue. With the Retarder off and accelerator off, the transmission should remain in gear attained and coast. However it instantly preselects 2 and starts to slow down and shift down as the engine speed allows until coming to a stop or adding pressure to accelerator to speed back up. They agreed this was not normal. They thought that they could fool the wire by putting a positive voltage on it. I did not like this type of a fix and left for home to return the next day and asked for another solution. The next day a few more hours of trying different things, each time we would take a trip of about 3 miles around a big square. Got pretty good at City of Houston driving coach in traffic. Each time the technician would make a recording and email it to Allison. One of the things they suggested was that the Silverleaf was causing an issue. So they moved their data input to the rectangular port above the round port and reconnected my Silverleaf so we could run their laptop and the Silverleaf at the same time. However they reluctantly admitted that the Silverleaf was not affecting the operation. Late in the second day Allison said that the retarder does not need to preselect a lower gear and suggested that they make the ECU disregard wires 119 and 163. The allowed the coach to coast as it should when not applying the retarder and even when applying foot brake. Now if I want to add engine braking along with Retarder, I must manually use the arrow on shifter to downshift. Not a seamless operation as it was before this issue reared its ugly head, but workable and much easier driving in stop and go traffic. It appears that Foretravel factory did something either physically or programming of ECU that allowed Preselect to come on upon engaging of Retarder. A conversation with Foretravel appears to be in order.
As long as you are comfortable using the down arrow and D, you are good!
Many of us have had an Allison dealer change the pre-select gear. I have mine changed to 5th.
Not a perfect fix, I intend to continue to pursue the correct fix. I am ok with operating it this way for now.
You don't have a coasting problem: You have a problem with your transmission downshifting when you don't think it should do so.
Why? Because you want it to do so?
LIke most people, they're idiots.
That's how Lynn learned where the right wheels are located except it was in Birmingham Alabama and the GPS was leading him in circles. I am smart enough not to mention the shiny sidewalls.
No! Really?
Why talk to Foretravel? You need to talk to an Allison expert who has the tools to re-program the automatic down shift to a gear you're most likely to use. Foretravel, bless their hearts, programmed yours for city traffic and city traffic speeds. Gotta slow down? The retarder engages and the transmission shifts from 3rd to 2nd.
If you get to east side of Houston, I have an Allison Guru
Upon your recommendation I called Lewis Large (Allison Trash Truck) (Expert Transmission) He came, worked three nights, and did all he could do. Lewis then sent me to Mid Coast(Allison transmission service). I went to Mid Coast on Lewis's recommendation. What did I do wrong. Do you have someone else who is an Allison Guru on the East side of Houston? Lewis seemed very competent, with the right equipment to analyze the transmission.
.
Are my expectations wrong? I do not expect it to try to downshift when I take my foot off the accelerator unless I have the retarder switch on and the joy stick pulled back. With the retarder off and accelerator off, I expect it to coast. That is the way it has worked until two months ago. That is the way my 2000 U320 worked, that is the way my 2007 Dynasty worked with a two speed engine brake.
Seriously, I am just trying to get my coach to work the way it did when I purchased it. I am not angry with anybody, just trying to work through this.
Herb,
Have you had the Allison ECU out of the coach at any time during your trouble shooting. I ask because when I had ours out for repairs (the dreaded snake eyes syndrome) I found a sticker on the back side indicating that a former owner had our trans reprogramed. Just wondering if your ECU has anything like that. See photo.
The funny thing is, on our coach since we have owned it, the "automatic downshift to 2nd gear" has never worked. We have a exhaust brake rather than a retarder, but the transmission doesn't know that. It is just supposed to get a signal from somewhere (?) to downshift when the "brake" is on. However, I have always been happy that it doesn't work - I would rather decide for myself when I want it to downshift and make the gear change manually. Different strokes...
You need the kind of Allison guy that can actually reprogram the electronics*. All he needs to do is change a parameter or two and all will be back to normal. How it got changed is not our problem. This is one of those mysterious computer things that just "is."
If Rudy's Guru is that kind of guy, then that's the guy you need.
*Not all repair shops, even manufacturer's shops are created equal. They each own a different sort of Allison franchise. I imagine the shops that can reprogram the ECU are at the top of the heap, and therefore the most expensive franchise to own and operate.
Lewis Large tried another Allison ECU, So did Mid Coast Transmission. Allison told them that the Retarder does not require the downshift, but the engine brake does.
.
Yep, Mid Coast was able to reprogram the ECU. They were in constant contact with Allison, sending recordings of test drives back to Allison and getting responses from Allison for programming adjustments to make. Allison recommended to program the ECU so that it disregarded the status of wires 119 and 163. Allison said that manufacturers (Foretravel) sometimes make changes to programming or wires that is non standard.
Herb,
Your expectations (to be able to COAST) are reasonable. Looking forward to the solution.
May be worth reaching out to John (Transmission Instruments (http://www.transmissioninstruments.com/)
See if he has ever run into this or has any suggestions.
Thanks, I put him on my list to call.
As you have said it worked perfectly until 2 months ago. So something happened then. If the
number 11 wire got shorted out some where that would cause the symptoms you are talking
about.
I was recently told that some Cummins engines have both Jake Brake and retarder, they were included in some engine builds that FOT bought, so it could be that you have this and the dash wiring is simply not hooked up. However some abrasion on a wire could perhaps create the situation you describe, it would also explain why the ECU swap did nothing.
I think the only way to find it is a long and frustrating search of the harness looking for such wear and tear.
I would start in areas that were recently worked on, looking for an inadvertent crimp or similar.
Hope you find the fix.
The retarder has nothing to do with the Cummins. The shifting down is caused by the transmission
computer shifting down to the program gear when the # 11 wire is grounded. When I wired up the
#11 wire I wired it to a separate floor switch so any time that my foot is off the throttle I can push the
floor switch to get the transmission to shift down and it will shift down to 2nd gear as the revs dictate.
My transmission is programed for 2nd gear which is what I wanted and I was lucky when I put in the
Jake the engine and trans computers were already programed.