Allison Transmission Questions

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

  1. Robert G

    Robert G New Member

    Allison Transmission Questions

    quote:Originally posted by AllisonMan

    Hi there. I have worked on Allison Transmissions for 27 years. If you have any questions, please post and I will check back once a week and try to answer them all. Thanks and have a great day! :)
     
  2. Robert G

    Robert G New Member

    Allison Transmission Questions

    Hi.
    New to this. I just bought a 1991 SportsCoach 35' with a 240HP Cummings and a Automatic MT643. It has a add on Jake Brake from the looks of the switch on the dash. My question is I know nothing about when to shift the transmission on hills at this time. Should I shift it or just leave it in drive and let it shift itself? Like i said i am new to all this. The jake brake I know nothing about so I just leave it off. I will be towing a 3500 lb car on a Dolly. I just took it to a RV sevice Center in Louisville KY and towing the car on the interstate the temp on the trans run about 200 to 250 from what I could tell. This was pulling the car and there were no big hills just small inclines. The trans seems to shift good and is very smooth. Going down a long hill should I shift it into a differant gear than drive? It has air brakes. Like i said I am new to this and like your site so I thought I would ask the Questions. I will be changing the trans fluid to Sys on the next service after reading about just changing the filter.
    Thank Robertg
     
  3. AllisonMan

    AllisonMan New Member

    Allison Transmission Questions

    OOfx,
    Mounting the cooler in the rear is normal IF the too cooler line from the transmission goes to the radiator tank cooler first, out the radiator tank to the oil to air cooler, out this cooler to the external filter, then back to the transmission. AT 542 and AT545 will heat more without the lock-up feature. They are run by hydralics which cause heat instead of lockup which locks the engine to the transmission.
    AT545 and 542 do not have much difference. The AT542 has a shallower pan than the AT545.
    As for the retarder option, only 1 school district in my area has them and there you talk about even more heat. I recommend due to the cost factor, of not installing the retarder. You also would need room on the right side of the transmission for a big valve that is mounted where your pto cover is.
    I hope I answered your questions. Thanks and have a great day! :)
     
  4. icrman

    icrman New Member

    Allison Transmission Questions

    Allisonman, could you please explain the operation of the trimmer valves? Thanks ahead of time.
     
  5. hfletcher

    hfletcher New Member

    Allison Transmission Questions

    Hi AllisonMan! I am about to install an MT643 into a Cummins powered Dodge pickup but I have recently been warned that this large tranny will rob excessive horsepower and significantly reduce my fuel mileage. I chose this tranny because my engine develops approximately the rated torque (700 ft lbs) of this tranny, and I want the lockup torque converter. Is it true that this will be a bad combination, i.e. large power loss and fuel mileage loss? Can these losses be mitigated by a specific torque converter ratio or by other means. I already own this rebuilt tranny. Thanks, Henry
     
  6. icrman

    icrman New Member

    Allison Transmission Questions

    The losses in the larger transmission should not be too much more than on a smaller Automatic transmission. Though some of the smaller units use a variable displacement pump that helps lower some of the pumping losses. If you use the truck for very heavy towing etc. I would think the Allison would be a good choice.
     
  7. buffalobilly

    buffalobilly New Member

    Allison Transmission Questions

    Allison Man, A little help please
    I need the bolt for the transmission throttle position senor cable on the fuel pump throttle arm. It is attached to the U shaped piece of metal about 1 inch wide and 3/16 inch thick. The throttle return spring attaches to the U piece of metal and the bolt is attached to the short end of the piece of metal. The bolt has a pin on the head side about 3/16 diameter and 1/2 inch long with a carter pin hole in it. The throttle position senor cable has a slotted end that the pin rides in, similar to the cruise control cable. The Transmission is a MD3060 hooked to a B-230 Cummins engine. .
    Need part # and vendor that can supply it.
    NOTE: It is not broken yet, but is worn over 1/2 way thought
    The unit is a 95 Safari Sahara
    Thanks

    12/21/04
    After an 1:30 on phone I found someone at Cummins South Plains in Tulsa that knew what I was talking about. About $4 for part and $10 shipping. Those folks in the parts dept. seem to know their stuff.
    no need to reply. Thanks anyway and merry Christmas.
     
  8. hfletcher

    hfletcher New Member

    Allison Transmission Questions

    Thanks icrman! Can we be more specific regarding hp/torque losses associated with an Allison mt643. Is there anything published in this area which would allow me to make a comparison with other transmissions? Thanks, Henry
     
  9. blodclot53

    blodclot53 New Member

    Allison Transmission Questions

    Howdy A. M.,
    I think you are more knowledgeable about stuff than just transmissions..

    I changed my front wheel bearings from grease to oil. I had synthetic oil put in. The maintenance interval for the oilers has never been clear to me and I have had different opinions. Some say to change the oil every year and some say they will go at least 100,000 miles before they need attention. Of course if oil is cloudy from contamination, etc., then they need attention sooner. Periodic check with a pencil magnet for metal wear is also possible. Shooting with an infra-red thermometer for increased heat would also be a method of checking.

    What is your opinion and is there a good site for "documented" maintenance intervals/procedures?

    My seals are Chicago Rawhides.

    thanks,
    george
     
  10. icrman

    icrman New Member

    Allison Transmission Questions

    It would be a bit difficult to be specific on the losses in the various automatic transmissions available. Unless you have access to a transmission dynomometer, or the engineering data from the manufacture. Modern Automatic Transmissions, and even some of the older Automatics are really very efficient. Too many people are under the false impression that an automatic is less efficient than a manual operated unit. I would say the automatic should actually beat the manual, because manuals in most cases use thicker oil, and have the gear sets constantly running in it. It is like a big cake mixer constantly churning that oil. And that robs power. Where as the automatic has in most cases one variable displacement pump, and the gear sets run in much thinner oil. (Fluid) The gears are not constantly submerged in the oil like the manual unit.
    To answer your question the only thing in the larger transmission that would create an increase in drag, is the size of clutch plates, when released there is a certain amount of parasitic drag on them. But I don't think it is enough to be concerned about. If I find some info I'll let you know.
     
  11. bulldog

    bulldog New Member

    Allison Transmission Questions

    hello allison man, i have a 96 4900 ih truck, ex fire truck, bought it wrecked. it has an allison hd 3060p trans model. we have the truck ready to go now and th trans would not light up, {its all electronic} we had an allison dealer check it out and found the shifter was bad. they used a test shifter on it said the trans was ok, truck only has 12065 miles on it. the price we got on the shifter was very high! i was also told it can be converted to a pad push button type, where can we get a reasonable shifter,even a used one, the top led board in mine is shorted, part # on shifter is 29514523 thanks for any help !!!! :)
     
  12. icrman

    icrman New Member

    Allison Transmission Questions

    Electronics is a good thing if your a manufacture, dealer, parts department. It is a bad thing if you are the end user, owner, mechanic, technician. Years ago when it all started going to electronics, I thought, to myself "lets see if the schematics and component level repair information will be readily available to the "non dealer - manufacture technicians"". Well it isn't. And that way they have you over a barrel. You get to pay the top dollar for their proprietary electronic black boxes. Personally I don't see why an automatic transmission needs any electronics. The old hydromechanical units worked just fine. For emissions, let the engine management system adjust, don't be slipping something in a transmission to do it. If you want to use some kind of electronic control on a transmission then just control the TV pressure with a solinoid valve.
     
  13. william phelps

    william phelps New Member

    Allison Transmission Questions

    Allison Man

    I wrote you a year ago about a repower project I am doing. I have a 28ft airstream motorhome and I want to diesel it. My goal is to have plenty of power and get some where between 14 and 17 mpg. I have a friend who has done a similar transplant and is getting this kind of mileage. My coach only weighs 12000 lbs. The motor I have purchased is 93 230 cummins with an allison 3060 tec11. The engine seems to be a good choice, but the trans is huge. I could save 300 lbs. with a 1000. Can a 1000 be mated to a mechanical cummins? Would the 3060 cost me milage over the 1000. Another question that is haunting me is, will the severe downshift of the 3060 be to harsh for such a light coach. Do you have any other Ideas for what trans I should choose?
     
  14. AllisonMan

    AllisonMan New Member

    Allison Transmission Questions

    1997 Beaver,
    Sorry about the delay, I have been trying to get all my christmas stuff done LOL. I have sent the CIN to my ofice and will check next week exactly what your ECU has in it. Thanks and have Happy Holidays! :)
     
  15. AllisonMan

    AllisonMan New Member

    Allison Transmission Questions

    cvrvr.
    Sorry to say, I have not found a "T" fitting yet but I will post as soon as I do. Thanks and have happy holidays! :)
     
  16. AllisonMan

    AllisonMan New Member

    Allison Transmission Questions

    Hi there William Phelps,
    You have a very good engine/transmission combination. Fitting it in will be biggest problem. The other choice I would suggest is if you could find a Cummins 5.9 with an Allison LCT2400, this would be a better combo. What you have will work. It is great transmission because you have 2 overdrives if the ECU is set up for all 6 speeds, this will be great for fuel milage. Downshifts should not be rough because the ECU of the world transmission will soften the shifts on its own as long as the throttle position sensor is working correctly. I would contact your nearest Allison distributor and have them run what is called a SCAAN run and it will tell you estimated fuel and also speeds for every gear. Thanks and happy holidays!
     
  17. AllisonMan

    AllisonMan New Member

    Allison Transmission Questions

    Hi GDM,
    Allison recomends changing fluid and filters again after the initial change to transynde at 12 months. After that the times spread way out. You may have already installed the gold filters if you purchased Allison genuine filters because I haven't seen any of the non Golds around for about 1 year. You can tell them because they say Gold Series right on the top of the filter. Allison is also recomending genuine gold filters with transynde for optimum change intervals. Thanks and have a great day! :)
     
  18. AllisonMan

    AllisonMan New Member

    Allison Transmission Questions

    Hello Bush,
    I always recommend synthetic Transynde if the coach is newer than a 1997-98. Your coach has worked fin for that many years, it will probably be fine for many more but at least with Dexron services closer together, you can have a qualified Allison technition test drive it and completly check it out when you get your service done (provided they are qualified to do so).
    so half they said is right but motorhomes are the best candidates to install synthetic TES295 transmision fluid as they sit long periods which causes condensation inside the transmission which breaks dow oil viscosity. With Transynde, I have yet to see a vehicle where the viscosity levels warrant change of the fluid. It is great oil. Thanks and have a great day! :)
     
  19. AllisonMan

    AllisonMan New Member

    Allison Transmission Questions

    Robbieandteresa,
    Amsoil synthetic transmission fluid is NOT Allison approved. Do not listen to the salesman. Have them show you the license that it is an approved "TES295" fluid. See how red their face will get. It will be on the container of fluid. If you go to allisontransmissions.com, you can get to the approved fluid section. As of Friday, I just checked and there are 4 choices and Amsoil is NOT one of them.Your motorhome will have to have a serial number above what Allison says (I am at home not office so I do not have them here) and any Allison distributor that does the change can set up your warranty from 3 years to 5. Your tag shoud say it is a MH.... transmission. The MH stands for motorhome and with that you are eligable to recieve with the transynde conversion, a 5 year warranty instead of the 3 year standard (valid after checking serial numbers also) Thank you and have a great day! :)
     
  20. AllisonMan

    AllisonMan New Member

    Allison Transmission Questions

    frfd,
    Sounds like you have the perfect transmission set points. In a perfect world say you have what we call a 2200rpm transmission, all 4 shifts would be exactly the same at 2200rpm. That rarely happens. If you ever would like to do minor adjustments to raise or lower the shifts, remove the pan and there are 4 adjusting rings on one side of your valve body. the 3 that are on the same side as the shift valve are in order from closest to valve, 2-3, 3-4 and 4-5 shifts. There are 7 different steps on the adjuster and the lowest step will give you the lower shift and as you go up notch by not, it will give you approx. 25 rpm higher. The only worry you shou;d have is if the shifts are too far apart or change from this point because then you may have a modulator issue but for now, it sounds solid. Thank and Happy Holidays to you and all your fellow firefighters! :)
     

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