Doug Hoegh Posted June 19, 2023 Share Posted June 19, 2023 (edited) 06 Diplomat with ISL400/Allison 3000. On our way to Alaska my transmission went into limp mode and is stuck in third. When it does this the two digit display on the shift pad indicates the right digit only as three and the check transmission light comes on. If I stop and turn off the coach the check transmission light will go out and the keypad goes back to 6/1. But then if accelerating goes back to the single 3 and check light returns. From the research I’ve found it either points to a sixth speed ratio issue or a speed sensor issue. We are in Haines and I can’t find any help so far but still looking. I’m going to confirm the connections at the twenty pin connector is tight and. It damaged. Looking for any other ideas. Thanks. Doug Edited June 19, 2023 by Doug Hoegh Link to comment Share on other sites More sharing options...
Dr4Film Posted June 19, 2023 Share Posted June 19, 2023 (edited) I had a similar problem while driving the Dynasty home from Salt Lake City except the Allison would not shift out of 1st gear. The code I got from the keypad was for the Output Speed Sensor. I fixed it by disconnecting the Output Speed Sensor at the rear of the transmission then cleaning the contacts in both connectors really good with a good contact cleaner. I don't see a P-0729 code in the Allison Code List. Are you reading the code correctly? Here is the Allison manual with the list of codes. Allison Trans Codes.pdf Edited June 19, 2023 by Dr4Film Link to comment Share on other sites More sharing options...
Dr4Film Posted June 19, 2023 Share Posted June 19, 2023 Also, the code I retrieved from the keypad at the time was 22 - 16 which is noted in the code list as Output Speed Sensor. I actually called an Allison dealer located in AZ where I had parked for the night who stepped me through how to retrieve error codes from the keypad. I thanked him for showing me how to do that. Learned something new that day. Link to comment Share on other sites More sharing options...
TW Racing Posted June 19, 2023 Share Posted June 19, 2023 I am not getting a code, only a check transmission light on dash and a N on push button selector. If I shut it off , it will go back to showing NN and go into gear for another 100’ then I lose power and go back to a single N. Link to comment Share on other sites More sharing options...
Tom Cherry Posted June 19, 2023 Share Posted June 19, 2023 Have you cell coverage and called Allison. They are very helpful and seemed to readily available…. Link to comment Share on other sites More sharing options...
Dr4Film Posted June 19, 2023 Share Posted June 19, 2023 24 minutes ago, TW Racing said: I am not getting a code, only a check transmission light on dash and a N on push button selector. If I shut it off , it will go back to showing NN and go into gear for another 100’ then I lose power and go back to a single N. Are you stuck in Alaska also? Link to comment Share on other sites More sharing options...
Scotty Hutto Posted June 19, 2023 Share Posted June 19, 2023 @Steven P had a similar problem a while back (last year?). Turned out to be a cable rubbing against the frame (?) had severed a wire. The Allison tech patched the wire in the field and everything has worked since. Simple fix, but hard to find. I’ll message Steven and see if he can log on and give more specifics. Since he also has a 2006 Dip I’m hoping there’s some similarity. Link to comment Share on other sites More sharing options...
TW Racing Posted June 19, 2023 Share Posted June 19, 2023 We are outside of Williams AZ. Thank you for all the information and going to call Alison now. Much appreciated!! Link to comment Share on other sites More sharing options...
Dr4Film Posted June 19, 2023 Share Posted June 19, 2023 18 minutes ago, TW Racing said: We are outside of Williams AZ. Thank you for all the information and going to call Alison now. Much appreciated!! When I was stuck in AZ, I called the Allison shop in Phoenix for help. They stepped me through how to retrieve any error codes to determine the cause. They were very helpful! Link to comment Share on other sites More sharing options...
Gary Cole Posted June 19, 2023 Share Posted June 19, 2023 (edited) After reading many posts of this sort I looked at my schematic some time ago and noticed that there were 2 sensors in addition to the speed sensor that could shut down or disable. Maybe more, didn't spend too much time looking at. One was a n.o. contact and the other was a resistance sensor. I thought at the time that they could be bypassed quite easily and temporarily with a jumper and a fixed resistor. Many of the problems were wiring or faulty sensor related. Wonder if any of the trans gurus here have given this method of getting home any serious thought? I really hate being stranded and at the mercy of the closest mechanic. Edited June 19, 2023 by Gary Cole 1 Link to comment Share on other sites More sharing options...
TW Racing Posted June 19, 2023 Share Posted June 19, 2023 I spoke to a gentleman at S n K transmission that are the Allison rep I believe in AZ. He was very helpful,but without a code it’s hard to tell. I push the arrow buttons twice for a code, is there another method? Link to comment Share on other sites More sharing options...
Dr4Film Posted June 19, 2023 Share Posted June 19, 2023 (edited) @TW Racing When you check transmission oil level, do you do it with the keypad or the dipstick? If you use the keypad then your Allison has a digital oil level sensor. Pushing the UP and DOWN arrows simultaneously once will put you into Oil Level Check mode. Pushing them a second time will put the keypad into Diagnostic Code display. It will then start listing the code(s) one at a time starting with d1. If you have more than one code you use the mode key to switch to d2, d3, d4, d5. Follow the directions listed in the PDF I had posted earlier. Edited June 19, 2023 by Dr4Film Link to comment Share on other sites More sharing options...
TW Racing Posted June 19, 2023 Share Posted June 19, 2023 I check with a dipstick Link to comment Share on other sites More sharing options...
Dr4Film Posted June 19, 2023 Share Posted June 19, 2023 41 minutes ago, TW Racing said: I check with a dipstick I guess your Allison doesn't have an oil level sensor to read the oil level on your keypad therefore according to the instructions you only push the arrows once to get into diagnostic mode. Link to comment Share on other sites More sharing options...
Tom Cherry Posted June 19, 2023 Share Posted June 19, 2023 1 hour ago, TW Racing said: I check with a dipstick NOTE TO ALL…. @Doug Hoegh & @TW Racing The 2006 Diplomats have the Allison MH transmission, from the Sales Brochure. There are several posts out there that date back to early 2006 that describe the method for checking the Oil Level and the keypad is supposed to be used and is way more accurate than the “dip stick” which varies from manufacturer to manufacturer as to the proper one and length….therefore use the electronic and key pad. BUT….bummer, the engine and tranny need to be at “operating” temperature to work, accurately. However, that same system will give you the codes….as Richard’s post says….and the diagnostics for that function is NOT a temperature item or necessity. The 2008 Cayman is a bit of a mystery. The sales brochure could not be found. BUT, i found the owners manual. The discussion starts on 208/9. On page 2012, there are two ways and the electronic OLS is outlined so it has the same “system” and is an Allison. There is also information on how it works and indicator lights and codes and such. If the build sheet is in the MH, it has the model and SN. Allison can and will help. Link to comment Share on other sites More sharing options...
Doug Hoegh Posted June 19, 2023 Author Share Posted June 19, 2023 (edited) Update our situation. After talking with my Allison dealer in Denver they showed me how to receive additional codes through the keypad. So I have three. 1. 6th gear not synch’d 2. Second gear not synch’d 3. Second gear valve stuck closed. The last code sunk my hopes for a quick fix. This valve is in the valve body assembly accessed by dropping the pan. So started to call around for help. Dealer in Whitehorse is 2 1/2 weeks out and couldn’t guarantee even then when they could get to me plus it’s a 250 mile tow round trip because there isn’t any heavy towing or trucks in Haines. Next option was Anchorage. If it’s even further away. So we made the decision to abandon Alaska and we a loading the coach on the Alaskan Ferry System and sailing to Seattle. Even that isn’t easy with the next open scheduled ship July 10th. So we are hanging in Haines until July with an appointment with Northwest Freightliner an authorized Allison dealer in Mt Vernon Washington. Edited June 19, 2023 by Doug Hoegh Link to comment Share on other sites More sharing options...
Tom Cherry Posted June 20, 2023 Share Posted June 20, 2023 25 minutes ago, Doug Hoegh said: Update our situation. After talking with my Allison dealer in Denver they showed me how to receive additional codes through the keypad. So I have three. 1. 6th gear not synch’d 2. Second gear not synch’d 3. Second gear valve stuck closed. The last code sunk my hopes for a quick fix. This valve is in the valve body assembly accessed by dropping the pan. So started to call around for help. Dealer in Whitehorse is 2 1/2 weeks out and couldn’t guarantee even then when they could get to me plus it’s a 250 mile tow round trip because there isn’t any heavy towing or trucks in Haines. Next option was Anchorage. If it’s even further away. So we made the decision to abandon Alaska and we a loading the coach on the Alaskan Ferry System and sailing to Seattle. Even that isn’t easy with the next open scheduled ship July 10th. So we are hanging in Haines until July with an appointment with Northwest Freightliner an authorized Allison dealer in Mt Vernon Washington. Obviously a bummer. We did Alaska via tour. My DW, a superb “homebrew” travel agent and tour director says that you can catch, she thinks, a nice one day cruise or “ship” into Glacier Bay. That would be s great thing to do as we have some fabulous photos. Just a suggestion. Bartlett Cove is the NP Visitor’s center. Google Ain’t much help. Look into it The day cruises start, from DW’s quick research there…. You are within maybe 1 1/2 hours of Skagway. They run eagle tours out of there. You ride up on a big ferry and then you do a rafting float (gentle and NO rapids) down the aqua colored streams and such. We LOVED that one. Google Skagway Eagle Tours…..there are several day tours I think that operate there. It is also “quite a place” just to wander around in. You are in the heart of a neat place. Lots of tours near you that folks fly in for. You might do some looking and luck into a discount if there are vacancies. You have 21 days….so, think out of the box and make the most of it…. Good Luck. Has anybody suggested hitting the tranny with a sledge to “fix it”? LOL….hang in there. You might want to do so “tourista” research for your time in Washington…. 1 Link to comment Share on other sites More sharing options...
timaz996 Posted June 20, 2023 Share Posted June 20, 2023 So sorry. That sucks. Link to comment Share on other sites More sharing options...
TW Racing Posted June 20, 2023 Share Posted June 20, 2023 I have tried to get a code and still no results, what’s a good number to contact Allison? Tom, sorry to hear all that you are going through. Link to comment Share on other sites More sharing options...
Steven P Posted June 20, 2023 Share Posted June 20, 2023 @Doug Hoegh @Scotty Hutto Sorry for the late response, long work day. However, mine seems different, esp w the codes. Mine ended up being wiring. The cable that left the tranny and went to the computer was ziptied at a sharp angle ultimately leading to a shirt in the wiring. New cable fixed it. Also Doug, the only transmission code port is in the engine hatch and mine was black. The engine ones are all gray. In case the tech needs help finding it like mine did. On a similar note, we had a neighbor whose old Mercedes hadn't been driven in years and the transmission wouldn't shift at all but the gear selector would. 4 quarts of transmission fluid and it shifted again. I'm guessing you checked the level? Best wishes! Link to comment Share on other sites More sharing options...
TomV48 Posted June 20, 2023 Share Posted June 20, 2023 5 hours ago, Dr4Film said: I guess your Allison doesn't have an oil level sensor to read the oil level on your keypad therefore according to the instructions you only push the arrows once to get into diagnostic mode. FYI. My book tells me I can check my trans oil level at the right rear corner, but I HAVE NO DIP STICK, ONLY THE ELECTRONIC oil level check at the key pad SO MAYBE HE HAS BOTH??? My oil fill related research says that Cummins does not install the engine dip stick as it is dependant on the build layout and the BUILDER to place it. Maybe in my case NO TRANS DIP STICK WAS HR's choice so maybe the oil dip is also a builder option AND MAYBE WE ALL HAVE ELECTRONIC CHECK TOO Link to comment Share on other sites More sharing options...
TW Racing Posted June 20, 2023 Share Posted June 20, 2023 I have tried using the gear selector for both OLS and codes with nothing showing up. I guess I will find out more when I speak with Allison tomorrow. I really appreciate all the feedback and advice. Link to comment Share on other sites More sharing options...
Tom Cherry Posted June 20, 2023 Share Posted June 20, 2023 9 hours ago, TomV48 said: FYI. My book tells me I can check my trans oil level at the right rear corner, but I HAVE NO DIP STICK, ONLY THE ELECTRONIC oil level check at the key pad SO MAYBE HE HAS BOTH??? My oil fill related research says that Cummins does not install the engine dip stick as it is dependant on the build layout and the BUILDER to place it. Maybe in my case NO TRANS DIP STICK WAS HR's choice so maybe the oil dip is also a builder option AND MAYBE WE ALL HAVE ELECTRONIC CHECK TOO I make this comment from reading lot and sitting through few Allison Tranny presentations at the Gathering. Many have attended more…so this is my take. The 3000 MH (maybe-probably? it’s big brother 4000) ALL came with the OLS (Oil Level Sensor/System) in the electronics….as standard. So, yes…motor homes could have a Dipstick, or NOT. Just because one had a dipstick did not mean that it was either or….maybe folks wanted the tried and true physical method. But Allison says or implies that the OLS is way more accurate based on how and the angle the tranny is installed. Past that, you can call Allison for more details. The info that i read in the 2008 Cayman owners manual said you could (in that model which DID have a physical dipstick) use either way, but my interpretation, perhaps tainted by what i think I knew, is that the electronic OLS is the preferred and most accurate. The issue with the OLS is being at operating temperature (engine & tranny) and level. BUT…the OLS gives error messages if the electronic sensors don’t read hot enough. ONE final note….a direct quote and instructions from Allison. If the level is 2 quarts….add ONE quart….drive 10 or so miles…. Then RETEST. NEVER add the full amounts….only in one quart increments. NOW….this is MY experience one step further. My Allison was serviced at 20 K and 45/50K. At 65K it was downshifting harshly when the Exhaust Brake was turned on. I checked the level. OL OK BUT I added maybe a quart and drove it. That took care of the abrupt downshift… checked then…OL OK….FWIW Allison Tech Support. 877-659-6913. US & Canada. International 1-336-970-5534…. Link to comment Share on other sites More sharing options...
Dr4Film Posted June 20, 2023 Share Posted June 20, 2023 (edited) 10 hours ago, TW Racing said: I have tried using the gear selector for both OLS and codes with nothing showing up. I guess I will find out more when I speak with Allison tomorrow. I really appreciate all the feedback and advice. @TW Racing Do you have the ignition key in the ON position with the Allison keypad lit up in red? Edited June 20, 2023 by Dr4Film Link to comment Share on other sites More sharing options...
Patrick Roman Posted June 20, 2023 Share Posted June 20, 2023 On 6/19/2023 at 8:41 AM, Doug Hoegh said: 06 Diplomat with ISL400/Allison 3000. On our way to Alaska my transmission went into limp mode and is stuck in third. When it does this the two digit display on the shift pad indicates the right digit only as three and the check transmission light comes on. If I stop and turn off the coach the check transmission light will go out and the keypad goes back to 6/1. But then if accelerating goes back to the single 3 and check light returns. From the research I’ve found it either points to a sixth speed ratio issue or a speed sensor issue. We are in Haines and I can’t find any help so far but still looking. I’m going to confirm the connections at the twenty pin connector is tight and. It damaged. Looking for any other ideas. Thanks. Doug That sucks Doug…and you haven’t even started on destruction highway parts of the Alaska highway if your in Haines. I’m thinking it’s a sensor or chafing wire issue the fun part is finding it. Have you tried manually shifts with the up and down buttons a friend had similar issues. It turned out his batteries were bad and didn’t have enough voltage to talk to the computer. Good luck hopefully you get to anchorage Link to comment Share on other sites More sharing options...
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