Allison transmissions and broken flexplates

Discussion in 'Class A / Diesel Pushers' started by RhumbRunner, Jul 7, 2009.

  1. RhumbRunner

    RhumbRunner New Member

    I have a 37' 2004 Newmar Kountry Star on a Freightliner chasis with a Cummins ISB 300 engine and an Allison MD3000 transmission which is all very nice when it runs but I have had 3 flexplate failures . The first in Aug/07 at 10,000 miles,the second in July/08 at 16,000 miles and the third in July/09 at 22,000 miles. Can I expect another failure in July of 2010 ??? None of the abovementioned manufacturers can explain the reason for the failures and I think they are just waiting out my warranty untill it expires in Sept/09.
    Has anyone else had problems with the same engine tranny combination like mine? - what caused the problem and how did they fix it.

    I need help!!!!!! :( :( :(
     
  2. C Nash

    C Nash Senior Member

    Re: Allison transmissions and broken flexplates

    Welcome to the forum Craig. Where is the flexplate breaking? Has the engine be boosted up? Did you buy it new? There is a Allision man, Danny Barton,here that will probably give you a good answer so hang around
     
  3. dbarton291

    dbarton291 Senior Member

    RE: Allison transmissions and broken flexplates

    What does the failure look like? Is the center torn out of the flexplates? Are any holes egg shaped? Where are you located and who has done the work? Have any of the repairing outlets found anything out of spec, or are they just replacing parts?

    This really sounds like a dimension in the system of adaptation parts is not correct. Allison has a service bulletin that lists all the required dimensions to prevent exactly the failure you are having. A good Allison shop will access to the latest version of this bulletin through the Allison extranet. What they are looking for is the bulletin that covers the TRANSMISSION ADAPTATION REQUIREMENTS.

    The adaptation requirement measurements must be followed completely. For example, one of the dimensions measures the flywheel housing face squareness to the engine crankshaft hub. If this is not square, the transmission sits at an angle in relation to the engine crank. This strain is taken up by the flexplates and they eventually break, usually tearing out the center of the flexplates.

    The shop has to make all the measurements in the bulletin and not take any shortcuts. An adaptation may be engineered perfectly, but if any of the parts involved (flywheel housing, flexplate to crank adapter, transmission converter housing adapter (if used), etc.) are out of spec, the flexplates can fail.

    The shop must make sure they have all the correct adaptation parts also. Allison will have an adaptation drawing of this adaptation, which is also available on their extranet. These drawings show the correct part numbers for the adaptation hardware required to properly adapt the engine to the transmission.

    They must also make sure all bolts are torqued to print.

    Depending on your answers to the questions in the beginning of this post, I may be able to offer some more specific suggestions.
     
  4. RhumbRunner

    RhumbRunner New Member

    RE: Allison transmissions and broken flexplates

    Hi Danny,

    Thanks very much for your reply.

    I am located in Toronto,ON,Canada -

    All three flexplates have had the centers torn out - no egg shaped holes that I am aware of.

    The first repair was done at 10,000 miles by Freightliner in Lincon,NE in colaboration with Allison in Omaha,NE - they claimed to have checked all runouts and they were within specs -they also claimed to have run the tranny on a dyno just to be sure it was OK.

    The second repair was done at 16,000 miles by Harper Power Products in Kingston,ON and Harper Power Products Ottawa,ON They also claimed that they had carefully checked all runouts and they were within specs -

    The third failure was at 22,000 miles and the RV is at Harper Truck Centers,Oshawa,ON
    they have checked all runouts and found them to be within spec. but have wisely refused to put in new parts and reassemble untill they find out what is causing the failures. They have given the problem to Allison and asked for help. So we are waiting for guidance from the head Mucklucks...!!!! The shop that the RV is in now appears to me to have the most experienced and professional employees I have encountered so far. They seem determined to "do it right". If only they knew what to do.

    I have suggested that a complete new engine + tranny would probably solve the problem,they agreed but advised that that probably would not happin. Fortunately this time the failure is close to home so I am able to give them the time to be sure the problem is found before they put in new parts and reassemble.

    Do you have any further wisdom to help us out of this mess?

    Thanks again for your help - we really need it.
    :)
     
  5. dbarton291

    dbarton291 Senior Member

    Re: Allison transmissions and broken flexplates

    Sounds like everyone that has touched this vehicle is saying they have done all the right stuff.

    I mentioned in my previous post about doing the adaptation measurements COMPLETELY, because it's common for shops to check the flexplate runout and depth and ignore the other, more difficult to make measurements. This one sure sounds like flywheel housing face squareness, flywheel housing bore eccentricity, or crankshaft hub runout. Excessive engine crank thrust may also contribute.

    Flywheel housing bore eccentricity is particularly tricky and requires repositioning the flywheel housing on the engine block to get it right. This measurement ensures the center of the flywheel housing bore is the same as the center of the engine crankshaft.

    Harper Truck Centers is an Allison overhaul dealer. I'm pretty sure the distributor in this area, which has a direct relationship to Allison, is Harper Power Products in Toronto. That's not a comment on the quality of either place's service. I just wanted you to know who you're dealing with from a business structure standpoint.

    My opinion would be to call Allison directly at 1-800-252-5283 and find out who is the Allison factory service person assigned to the area the vehicle is now in. I would contact that person directly and explain the history of this vehicle and ask his/her involvement in making sure ALL the adaptation measurements are done correctly and all the correct parts as per the installation drawing are put back in the vehicle.

    If there were egg shaped holes, that would indicate bolts are coming loose, but you don't indicate that is present. That's another set of possibilities.

    Now you know some more of what I know. It ain't much, but it's free and I hope it helps lead to the root cause.
     
  6. RhumbRunner

    RhumbRunner New Member

    Re: Allison transmissions and broken flexplates

    Hi again Danny,

    I tolk your advice and met with the Allison regional customer support manager Henry Marienfeldt ,Harpers service manager and a couple of mechanics. We were all gathered in Harpers service bay beside my RV with the tranny and many parts all over the floor. They had the adaption bulletin in hand and assured me that ALL of the measurments had been checked and double checked and that they were all within spec..................!
    The broken flexplate was there, the centre had been torn out, none of the bolt holes were egg shaped.

    The only variation to the bulletin seemed to be some differences in part numbers - they are checking with Allison engineers to see if the wrong parts were used or the numbers were changed without another bulletin being issued.

    The blame game then began starting with the possibility that the crankshaft damper was faulty - I don't think so the crank would have broken not the flexplate!!
    Then it was suggested that I had modified the engine - I have not ! but they are checking to be sure.
    That I have abused the transmission by using it in a way for which it was not designed - not true !!
    They are grasping at straws here.
    Allison trying to duck responsibility is not new to me - I have had to get Newmar,Freightliner and Cummins involved in my past encounters to get them to react in a responsable way to this problem. I will do it again if necessary.

    It would seem that the only positive suggestion that has come out of this event is the possibility of the wrong parts being used ?????

    What do you think?


    :angry: :angry:
     
  7. LEN

    LEN Senior Member

    Re: Allison transmissions and broken flexplates

    What if the Cummins Block was not square to the adapter plate would this show in the measurements.

    LEN
     
  8. RhumbRunner

    RhumbRunner New Member

    Re: Allison transmissions and broken flexplates

    Yes that is one of the measurements they check first :)
     
  9. LEN

    LEN Senior Member

    Re: Allison transmissions and broken flexplates

    Boy gottta be something if the block is square, both ends of the adapter plats are square, and the trans is square and the alinement of the input and output shafts are where they should be. the only thing left would be the torque converter. Thinking thinking boy at my age that gets tough.

    LEN
     
  10. dbarton291

    dbarton291 Senior Member

    Re: Allison transmissions and broken flexplates

    I smoked a good cigar tonight and thought on this one at length. A nice big 60 ring cigar. I don't normally get out the big fat ones unless the occasion is something special. This post is a one fat cigar answer, meaning I have chewed (meaning I thought about it. I don't waste good cigars by chewing on them) on this one for about an hour.

    I would as one suggestion at this point, involve Cummins. Engine irregularities are a possiblity as well as wrong parts. Gotta make sure it's 100% right according to the installation drawing. I don't know about this engine, but Cummins does supply the flexplates on some engines.

    I am not aware of any engine modification (like horsepower upgrades), or an operating condition that can cause this failure as the primary mode of failure and not show any other evidence of its presence.

    The only operational thing I can think of as even a remote possibility, is the vehicle sitting still with the brakes on, the engine at a high RPM and the transmission going into gear. But the transmission has a neutral to range engine speed inhibit built into its calibration to prevent this. Henry may have experienced something along those lines I haven't.

    Another remote possibility is to make sure the transmission calibration that's in the TCM is for a motorhome. Fire truck cals, for example, do not have some of the "consumer" safety inhibits in them to allow an emergency vehicle to move whenever the driver wants it to, in spite of things like high engine RPM.

    Operational stuff aside, I tend to agree with Len. It's gotta be something. Those flexplates can't handle a load that's being put on them. I'm sure I don't know everything, but my experience says the load those plates are experiencing has to be an excessive axial (front to back) movement, or they're trying to run elliptically as the vehicle is going down the road. Maybe the torque converter should be replaced in case the flexplate holes in the front cover are out of round in relation to the converter pilot on the front cover (the little nose that pilots the converter in the engine crank or crank adapter), or the converter pilot is off center, or the converter's rear hub that engages the pump is off center somehow.

    Has there ever been any evidence of a front transmission seal leak? That may, but not always, accompany an adaptation running elliptically. I think I'd replace all the adaptation parts and not reuse anything, too.

    I don't think it's the pilot hole in the engine crank because the adaptation measurements should have caught that. I also don't think it's the torque converter sitting too far inside the transmission case, because that's one of the adaptation measurements, too.

    Getting Cummins' input and replacing the converter and all adaptation parts are my best suggestions at this point, but I'm not 100% sure any of those things would be the primary cause. I'd hate to see it go back together at this point having not changed anything.

    When it does go back together, the tech should make sure the transmission slides easily into the engine flywheel house and doesn't have to be drawn up against the engine by tightening the mounting bolts. Also, the flexplate bolts should start easily by hand and not have to be forced through the flexplate holes into the torque converter.

    Please come back and post the outcome and the action taken. This is a stumper.

    My cigar is now burned down to where it's gonna burn my lips soon. I'm gonna hit the submit button and be checking back to see what they decide to do for this one. Please let us know what's done next.
     
  11. RhumbRunner

    RhumbRunner New Member

    Re: Allison transmissions and broken flexplates

    Hi Danny,

    No plan of action from harpers yet,only consensis point is that everyone agrees there is an axial/elliptical movement that is causing the failure. The cause of this movement is the $50 question.

    The flexplate is an Allison part that is why they are the secondary player

    There is no evidence of an oil leak in the transmission - we would have seen it as the transmission is removed from the vehicle and cleaned on an annual basis.

    You seem to have an excellent grasp and knowledge of the subject - how do you fit into this conversation?
    Are you involved in the trade? in what capacity?

    Would it help your further thought process if I sent you some really good fat cigars (Cuban,we get those here!)
    although I might be arrested for sending them cross border .......!!

    Thanks again for your wisdom,it really helps in my conversations and understanding what Harper and Allison are telling me.

    They sometimes have a tendency to treat you as if you just fell off a turnip truck.

    Will keep you posted of the happinings in this ongoing saga.

    Craig :)
     
  12. dbarton291

    dbarton291 Senior Member

    Re: Allison transmissions and broken flexplates

    I'm an old service guy and I'm just glad to help out when I have time. Answering questions for people helps keep my service skills sharp so I don't lose touch with the hardware folks pay good money for and expect to perform.

    The transmission is removed from the vehicle and cleaned on an annual basis?? I've not heard that before. Can you describe for me who does this work and the logic behind why this is necessary?
     
  13. LEN

    LEN Senior Member

    Re: Allison transmissions and broken flexplates

    I think the OP means that its had that much trouble that the repairs R&R have been annual.

    LEN
     
  14. dbarton291

    dbarton291 Senior Member

    Re: Allison transmissions and broken flexplates

    That sucking sound you hear is me pulling my foot out of my mouth.

    I can't believe I didn't get it.
     
  15. dbarton291

    dbarton291 Senior Member

    Re: Allison transmissions and broken flexplates

    I still can't believe I didn't get that joke........better have two cigars tonight and lighten up.
     
  16. RhumbRunner

    RhumbRunner New Member

    Re: Allison transmissions and broken flexplates

    Len got it.............!!!

    Yup - for the past three Augusts we have blown the flexplate, dropped the tranny and amongst other things cleaned it all up - you will note that no matter how clean we keep it it still breaks down. so we have eliminated it being durty as part of the problem.

    Still no word from the engineers.

    Craig :laugh: :laugh:
     
  17. dastout

    dastout Junior Member

    RE: Allison transmissions and broken flexplates

    You are a very patient man putting up with this problem for this long. I can understand why you feel dtermined to find the root cause of this problembut I can not help wondering if maybe it is time for a lawer(before the warranty expires) or maybe time to trade this sucker in!

    I wish you good luck, i hope they can determine what the actual cause is and admit it. But then again you will not know until another year or 10 to 15k miles are added.

    Keep us posted!
     
  18. RhumbRunner

    RhumbRunner New Member

    RE: Allison transmissions and broken flexplates

    Lawyers are a last resort - mostly they win you lose !!

    Diagnostic process with this problem is very slow - no word at all from Allison,obviously they have no clew at all as to what is causing the failures.

    The RV is still in one of Harpers bays in everybodys way - which is a good thing since all the Mechanics see it all day everyday and they all have their ideas as to what is breaking up the flexplates - one of them got to examining the flywheel and found that the ring gear is not mounted properly and he felt that might have put the flywheel out of balance enough to cause the flexplate to try to dampen out the imbalance movement caused by the flywheel and then fail from the constant movement.

    That theory sounds plausable to me becouse the failures are at regular intervals,which would indicate that an outside force is placing constant and unusual forces on the flexplate, but could an inproperly mounted ring gear create a condition that would make the flexplate flex enough to fail ?

    Allison was advised of this discovery and we await to hear what their engineers have to say.

    Good thinking Mechanic here - what do you think .........?

    Craig :) :)
     
  19. dbarton291

    dbarton291 Senior Member

    RE: Allison transmissions and broken flexplates

    Possible. That's another reason to involve Cummins. Get the balance spec on the flywheel from Cummins and have it checked out. Or, just replace it.
     
  20. dbarton291

    dbarton291 Senior Member

    RE: Allison transmissions and broken flexplates

    Assuming it's a cummins flywheel and not something Allison provided.
     

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