Allison Transmission Questions

Discussion in 'General RVing' started by AllisonMan, Apr 5, 2003.

  1. dbarton291

    dbarton291 Senior Member

    RE: Allison Transmission Questions

    Glad it's fixed. I guess this was one of those where we should have remembered to always to the cheap and easy stuff first.
     
  2. Tufaw

    Tufaw New Member

    RE: Allison Transmission Questions

    In all fairness I must say that the new TPS was my idea before I even called Allison. After discussions with the Allison folks we agreed the problem exhibited all the characteristics of an electrical component failure (TECL) rather than a bad connection. This problem would cure itself every time if you turned the engine off and then restarted it. Shortly after it would fail again. It looked as if it was a flaky electrical component in it's final death throes. It would appear that water ingestion and oxidation/corrosion situation can manifest itself in a consistent and repeating electrical fault like a failing component.

    Rob
     
  3. Danl

    Danl New Member

    Re: Allison Transmission Questions

    Allison men. I have a 96 MONACO 8.3 and md3060. About 6 months ago the trans developed a rpm flare between 3rd and 4th. It doesn't happen all of the time unless I'm pulling a trailer. I had the fluid and filters changed but no change. I checked the tps (King control) and it checks OK.

    Dan
     
  4. dbarton291

    dbarton291 Senior Member

    Re: Allison Transmission Questions

    How many miles on the unit?
    How heavy is the trailer?
    How many RPM is the flare?
    Does the flare occure a few times and then stop? Or with the trailer hooked up, does the flare happen each and every time for many repititions of the 3-4 upshift?
    Any trouble codes?
     
  5. Danl

    Danl New Member

    Re: Allison Transmission Questions

    The unit has 69000 miles. The trailer weighs about 8500 lbs. Rpm flares 500-800 RPM. It happens almost every 3-4 shift once the trans warms up when pulling and sometimes when not pulling. Had a code for the oil level sensor but I had it replaced. No codes now. Can the tcm be reprogrammed to act like a tow/haul mode on a gm truck? Instead of having economy mode reprogram to shift later while towing? What I have been doing is putting the trans in 3rd and shifting manually to 4th at a higher rpm. This seems to work about 90% of the time. Thanks in advance for your help
    Dan
     
  6. dbarton291

    dbarton291 Senior Member

    Re: Allison Transmission Questions

    I'm assuming you're at wide open throttle when this happens.

    Assuming wide open throttle, a 500-800 RPM flare on the 3-4 upshift that is consistent is not normal. By adding 8500 pounds, you change the gross vehicle weight the transmission's adaptive controls have adapted the shift quality to and that will cause a flare. But, after making the 3-4 upshift (at the same throttle position) several times, the shift should have re-adapted and the flare should be gone. That also indicates you probably are operating with an economhy shift schedule because if the upshift point was near engine governed speed, there isn't 500 - 800 RPM left in the engine's speed range to flare into.

    The TCM has in it the ability to have two shift schedules. In many motorhomes, the pressing of the mode button changes the shift schedule from economy to performance or vice versa. The performance shift schedule should upshift closer to the engine's full load governed speed, but you must be at or near full throttle.

    If you don't have any original documentation, you can take the vehicle to an Allison outlet that has the DOC software and determine which shift schedules you have in which mode (they're called primary and secondary). If you don't have a performance mode, with a shift schedule that has its wide open throttle upshifts near the engine governed speed, it can be reprogrammed, but you may have to shop around on price.

    This still begs the question as to why the transmission is flaring and not correcting itself. You may have an internal transmission issue. But because of the 8500 pound GVW change this vehicle gets, my personal opinion would be to try to address it with calibration first.
     
  7. Danl

    Danl New Member

    Re: Allison Transmission Questions

    Thanks for the reply. The 3-4 flair occurs at almost any throttle position. I only use full throttle in 5th climbing hills. When
    I had the filters and level sensor changed they said the trans was clean inside. I sure hope that there is no internal damage.
    I read an earlier post that said that there was some problems with case cracks in the early units. I sure hope there is no truth to that. Do you have any suggestions on where to get the TCM reprogrammed?
    Thanks Dan
     
  8. dbarton291

    dbarton291 Senior Member

    Re: Allison Transmission Questions

    case cracks in early units were around the main filter area. In extreme cold it was possible to get a pressure spike that might damage the case. It would be obvious if you had that. For reprogramming, go to www.allisontransmission.com and use the service locator to find an authorized Allison outlet near your area.
     
  9. tsanders

    tsanders New Member

    RE: Allison Transmission Questions

    Hey there. I am new to this site and have a question dealing with my allison transmission. It is a 3000 rds and I am getting a 2312 code that I am struggling with. any ideas? Thank you
     
  10. dbarton291

    dbarton291 Senior Member

    RE: Allison Transmission Questions

    An RDS? What's it in?

    Is the selector integral with the ECU(TCM), or remote?
     
  11. LEN

    LEN Senior Member

    Re: Allison Transmission Questions

    I found this, just a search and I know nothing!
    2312 Timing Actuator #1 Circuit Error

    And here what to check for

    23 12, 13, 14,
    15, 16
    Check:
    a. ECU connectors are tight, clean, and undamaged.
    b. Shift selector connector is tight, clean, and
    undamaged.
    c. Wiring harness has no opens, shorts between
    wires, or shorts to ground.
    d. Shift selector(s) for proper operation.
    Shift Selectors

    LEN
     
  12. brodavid

    brodavid Senior Member

    Re: Allison Transmission Questions

    good going Len
     
  13. dbarton291

    dbarton291 Senior Member

    Re: Allison Transmission Questions

    Yup, that's pretty much it!

    If the selector is remote, special attention needs to be paid to the harness between the selector and the ECU. If the selector is integral, you can have a problem with the ribbon cable that connects the selector to the circuit board in the ECU.

    As a last resort, replace the selector, then the ECU. Normally though, it's in the wiring, or it's a connector terminal that's loose.
     
  14. jbman45

    jbman45 New Member

    RE: Allison Transmission Questions

    Hello Allison man if you're out there! Trying to leave on a trip this week and just found out my 3126E with allison 3000 shifts badly; throws an error code for d1 of 22 14 which says engine rpm sensor? Also the oil level indicator shows code 95 which the book shows as sensor inoperative.

    Had an issue awhile back while I was laid up with a bad hip, dog jumped under motor home many times and knocked off the sensor wire toward the front of the transmission, sort of on engine/trans interface or bell houseing.. Is this the speed sensor?? Any way to check sensors or wires to see if they are working?

    thanks for any help.
     
  15. dbarton291

    dbarton291 Senior Member

    Re: Allison Transmission Questions

    The sensor on the converter housing of the transmission is the engine speed sensor. You can check for opens, shorts between wires and shorts to ground with a digital volt ohm meter. I would fix the engine speed sensor problem first and see if the oil level sensor problem recurs, in case they share a circuit. There's one sensor ground that is common to more than one sensor, but I can't remember all the details right now.
     
  16. dbarton291

    dbarton291 Senior Member

    Re: Allison Transmission Questions

    I forgot your other question. To see if the sensors are working requires a diagnostic tool. Your best bet is to make sure the wires to the engine speed sensor are good and the connector and terminals are in good shape. The trans computer will produce a trouble code if something in the sensor or circuit is not functioning. Remember to clear the codes when you are done. Good luck!
     
  17. jbman45

    jbman45 New Member

    Re: Allison Transmission Questions

    thanks so much db291, I'll go over it again tomorrow and recheck all connections, all look pretty good but I'll pull apart and spray clean. Any chance you know if there is a control module for the allison? or is it tied into the cat or engine service plug diagnostics. somehow I feel it's a bad wire or connection and maybe if I could find the darn ecm for the allison I could check it there too. I can only find the wires going to the keypad.

    thanks for your help...
     
  18. dbarton291

    dbarton291 Senior Member

    Re: Allison Transmission Questions

    There is a separate controller for the Allison. It is correct procedure to check the wires for the sensor from the controller to the sensor. That way, you get a complete circuit check.

    If you follow the wires from the keypad, they will end up at the transmission controller.

    Since there was an animal under the vehicle, you probably should take a look at the main transmission connector while you're at it. If any of the wires going into that connector look damaged, that might be the cause of the oil level sensor problem.
     
  19. jbman45

    jbman45 New Member

    Re: Allison Transmission Questions

    Thanks dbarton291; you were on the right track and helped a lot. Although I checked sensor with another, wires best I could for connection did not get it resolved so took it to a local Stevens/Stewart place and boy are they on their stuff. They agreed with you probably a connection and it turned out was the speed sensor connector! Hard to see from my standpoint since the receptacle pins were pulled back into the connector and contact was not made. Simple 5 dollar part and fixed. Also you were right on fixed the speed sensor and the oil level indicator problem resolved itself.

    Thanks and I compliment you on knowing your stuff and willingness to help out.

    best and have a good 4th....
     
  20. dbarton291

    dbarton291 Senior Member

    Re: Allison Transmission Questions

    Thanks. Glad to help and hear about the resolution to the problem. Which Stewart & Stevenson location did you visit?
     

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