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Thread: Alison Tranny Retarder vs Jake Brake

  1. #1
    Join Date
    Nov 2006
    Location
    Sugar Land, TX
    Posts
    1,307

    Question Alison Tranny Retarder vs Jake Brake

    We test drove an 01 Liberty Classic Lady when we were in Florida last week, and it had the Alison 6 Speed Transmission Retarder. I just loved it.

    What is better, Jake Brake, Tranny Retarder and why?

    Can you guys give me the pros and cons of having one or the other, please so I can either rule out trying to find a used bus with one or the other in it?

    Gary

  2. #2
    Orren Zook Guest

    Default

    Well, you'd never have to worry about the dreaded 'no engine brake' signs with the trans retarder.... I've always had Pac or Jacobs exhaust braking on my diesel coaches and it has worked well, plus I like the noise they make. I understand that the fluid temperatures need more monitoring with the retarder because of how it works.

  3. #3
    Join Date
    Jan 2006
    Location
    Alexandria
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    2,161

    Default

    Gary,

    I have the retarder on the Liberty and it works fine, although you really have to pay attention to the transmission fluid temperature as it's easy to exceed 230 on some hills. You'll probably fine the concesus being the jake is better. That being said it would be pretty far down my list of considerations for the "perfect" bus.

    Mike

  4. #4
    dreadnought Guest

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    I was temporarily brain dead and pricing a new Liberty
    earlier this year. Was told all new buses come standard with retarders and a Jake would lower the price by 6 grand! I can't understand why anyone would pay an extra 6K to boil their tranny oil. Jakes have been around forever, work great and are just about bullet proof. My old used bus came w/the retarder, works ok, but I can't help feeling there's a plot involved to sell transmissions.

  5. #5
    Join Date
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    anytown
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    Default

    We had a Jake on the first coach and have a retarder on our current coach.

    This is strictly an opinion so take it for what it is worth. We would never again want a coach with a retarder. Our reasons are fairly simple. The Jake does not have an adverse affect on anything. It does not raise temperatures so using it at its full setting constantly does not require anything of the driver.

    The retarder seems to have more holding power. It has a broader range of retarding power than a Jake so you can select a retarding force suited for the hill, and if the retarder is on, applying the brakes also adds retarder force to assist with braking. When using brakes heavily with the retarder on will drive the temperature up rapidly.

    As Mike points out, it heats up the transmission. Heat will damage the transmission fluid and the transmission, so for those who have a coach with a retarder and a transmission temperature gauge you have to monitor the temperatures. For those with newer coaches, Prevost allows you to monitor the transmission temperatures, but you have to go through some gyrations to get at that information through the Pro-Driver. Maybe Prevost feels ignorance is bliss so they eliminated the temperature gauge on the new dash.

    I have no clue what a safe transmission oil temperature is because there are no limits that I can find defined anywhere. I arbitrarily use 230 degrees just because the red line for oil on my plane is 240. If someone knows what the real limit should be please post it.

    This is an observation but with all the sensors and computer power now in place it seems to me that if the temperatures get too high, the computer could reduce the retarding force until temperatures return to a normal range, but the flip side of that is that Allison and Prevost will spend a lot of time in court because any time braking or retarding force is reduced it could have dire consequences.

  6. #6
    Join Date
    Jan 2006
    Location
    Jasper
    Posts
    3,775

    Default

    Ditto Jon's comment.. I've had both and with a previous Foretravel running out west in the real mountains, the trans temps where a real concern with the retarder. Go with the Jake, it's bullet proof!

  7. #7
    rvbus01 Guest

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    Retarder Operation -- How Does It Work?


    The retarder is at the output of the transmission and consists of a vaned cavity and a vaned rotor which is splined to and driven by the output shaft. When the retarder is activated, fluid is directed into the retarder cavity. The interaction of the fluid with the rotating and stationary vanes causes the retarder rotor speed, and the output shaft, to decrease and slow the vehicle.



    When the retarder is deactivated, the retarder cavity is evacuated.



    Additional retarder information can be obtained by ordering our free Motor Home video, "Operating the Allison MH Series Transmission" (VI3424EN). Click on this link for ordering details.



    Motor Home Video



  8. #8
    Join Date
    Feb 2006
    Location
    Bristol, Tn
    Posts
    1,647

    Cool Retarded

    That is not a misprint, I meant retarded. I too have the retarder and I can not go anywhere unless I am up and down the hillls because of the area I live in. I have to use it constantly. I believe it was designed for flat areas. Not only can you cook the tranny oil, the tranny then will shift very hard and feels like it will jerk something loose until it has gone thru enough shifts to wash the retarder from its memory.

    If I was in the process of evaluating a new to me coach purchase the retarded would not prevent me from purchasing it, but would definitely get a check on or in the minus column.

    We have had similar discussions on one these forums before about this, and we have yet to come across anyone who truly understands the benefits of the retarded over the jake.

    I am in agreement with Jon and Toms remarks.
    Roger that!
    2008 Liberty DS XL2
    2023 Denali Ultimate
    My 6th Prevost

  9. #9
    Join Date
    Nov 2006
    Location
    Sugar Land, TX
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    1,307

    Default Wow

    That is why I am glad I joined this group, especially before I purchased a bus. The information you guys spew ( a good thing ) forth is just fantastic.

    I learn so much from reading all of your posts, I just can't stand it.

    Thanks again for all of the invaluable information.

    Any of you going to be at the Tampa RV Show? Are you in your bus, or staying at a Hotel.

    Peg and I are flying in Friday night the 19th, and staying at the Red Roof Inn, which I believe is next to the fairgrounds, and checking out all the bus's, Saturday and Sunday.

    Call if you are in the neighboorhood. 713-252-2599

  10. #10
    Join Date
    Jan 2006
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    anytown
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    Default

    Gary,

    I'll take a 180 turn here.

    If you find a coach you like don't make the decision to walk away from it because of the retarder.

    You see how most of us feel, but it does not have to be a show stopper. First of all a retarder works. It assists in braking and it will help control speed going down hill. A Jake allows the driver to be less attentive, but to make a retarder work effectively and not overheat you as the driver has to plan ahead and that is not a bad thing. I get the best compromise by leaving it in the second position and slowing down slightly just before the steep downhill. That keeps the bus going downhill at a reasonable speed and it keeps the temperatures very low.

    With a Jake you can be going fairly fast, and put it in the high setting and downshift and it will do a great job and you don't have to worry about it, but these buses are more than just retarders.

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