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    Guest Message by DevFuse
     

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    Mack 12 Speed



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    17 replies to this topic

    #1 OFFLINE   sodly

    sodly

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    Posted 29 May 2008 - 07:10 PM

    Can someone please explain the shifting pattern in a (1993) Mack 12 speed transmission? Sorry, I don't know the number. I'm coming from a Fuller 13 speed Roadranger and I'm trying to figure out how different it is to drive a Mack 12. Thanks.

    #2 OFFLINE   ThaddeusW

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    Posted 29 May 2008 - 08:19 PM

    Can someone please explain the shifting pattern in a (1993) Mack 12 speed transmission? Sorry, I don't know the number. I'm coming from a Fuller 13 speed Roadranger and I'm trying to figure out how different it is to drive a Mack 12. Thanks.


    Sodly,
    The 12 Speed Sort of shifts like a Super 10. you have 5 gears and you split each one from first to fifth. you can use any of the five gears in reverse. the other 2 gears come in by flipping the dash switch or second stick into low. You then use 1st in low or high split as 2 very low crawler years.
    -Thad
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    #3 OFFLINE   HK Trucking

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    Posted 29 May 2008 - 08:24 PM

    Can someone please explain the shifting pattern in a (1993) Mack 12 speed transmission? Sorry, I don't know the number. I'm coming from a Fuller 13 speed Roadranger and I'm trying to figure out how different it is to drive a Mack 12. Thanks.


    5 speeds on the stick in the standard "H" pattern, reverse is on the air shift knob, enabling the use of all 5 speeds in reverse as desired, also on the air shift knob is a hi/lo splitter which you can use to split each of the 5 gears in half, similar to operating a 2 speed rear.

    Depending on the vintage of your 12 speed, it may have another shift lever for the deep reduction off road lo range, or if it's a newer one (TRTXL1070B) it will have an air switch on the dashboard for the deep reduction.
    "If You Can't Shift It Smoothly, You Shouldn't Be Driving It"

    #4 OFFLINE   sodly

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    Posted 29 May 2008 - 08:38 PM

    5 speeds on the stick in the standard "H" pattern, reverse is on the air shift knob, enabling the use of all 5 speeds in reverse as desired, also on the air shift knob is a hi/lo splitter which you can use to split each of the 5 gears in half, similar to operating a 2 speed rear.

    Depending on the vintage of your 12 speed, it may have another shift lever for the deep reduction off road lo range, or if it's a newer one (TRTXL1070B) it will have an air switch on the dashboard for the deep reduction.


    Okay... the one I was looking at had the reduction switch on the dash. But... how do you get 12 speeds outta 5 x 2? Where are the other two gears hiding? Or, how many of the 12 do you normall use in normal driving? For instance, if you're empty can you just use 5? Thanks.

    #5 OFFLINE   HK Trucking

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    Posted 29 May 2008 - 09:17 PM

    Okay... the one I was looking at had the reduction switch on the dash. But... how do you get 12 speeds outta 5 x 2? Where are the other two gears hiding? Or, how many of the 12 do you normall use in normal driving? For instance, if you're empty can you just use 5? Thanks.


    5x2 without deep reduction = 10.

    1st gear with either the high or low split while in deep reduction =2.

    Total of 12 speeds.
    "If You Can't Shift It Smoothly, You Shouldn't Be Driving It"

    #6 OFFLINE   HK Trucking

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    Posted 29 May 2008 - 09:28 PM

    To answer your other questions, you can use all the combinations or whatever you need to keep the engine RPM's in the proper operating range depending on conditions.

    When empty you can drive it like a 5 speed if you want.
    "If You Can't Shift It Smoothly, You Shouldn't Be Driving It"

    #7 OFFLINE   sodly

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    Posted 29 May 2008 - 10:33 PM

    So, not to sound too ignorant here... two of the gears are "deep reduction"... meaning granny low gears? Is that right? In that case you have 10 speeds for normal road operation? Thanks.

    #8 OFFLINE   Lmackattack

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    Posted 29 May 2008 - 10:42 PM

    you can split all 5 gears on the stick...that gives you 10 forward speeds
    the dash swith puts the trans in low reduction then the splitter on the gear lever can split that gear giving you 2 more speeds in "low Low"

    thats a total of 12 speeds

    Its a great trans as you have all the low gears and a good OD. Normal driving I would shift it 1-2-3-4 than split 5.. almost like a 6 speed. then in the hills you can split the gears to keep RPMs/speed up.

    They are getting scarce and expencive to repair!

    #9 OFFLINE   sodly

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    Posted 29 May 2008 - 10:55 PM

    Oh, I see. So first position on the shifter really handles 4 different gears (when you count all the splits... one regular split and one lo/lo-lo split). All the other positions (2,3,4,5) contain only 2 gears each.

    #10 OFFLINE   brutus998

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    Posted 30 May 2008 - 08:38 AM

    Oh, I see. So first position on the shifter really handles 4 different gears (when you count all the splits... one regular split and one lo/lo-lo split). All the other positions (2,3,4,5) contain only 2 gears each.



    Sodly you are correct. All the way over and down is low and low-high(1st and 2nd gear). Let me tell you they are turtle slow when you have the low-range locked in!!!! Really you would want to start off in 3rd. Unless on a hill you can just keep in direct and shift like a 5 speed, then split the last one for Over-drive. Now most 12 speeds that I have seen will raise the bed with the shifter. Kick in PTO then make sure shifter is in neutral then put in gear and it will raise your bed. !st gear raises bed real slow and 3rd raises super fast. It really is a sweet tranny. You can grab 5 gears in reverse just like the old 6 speeds.

    #11 OFFLINE   brutus998

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    Posted 30 May 2008 - 08:41 AM

    Oh I also forgot to tell you. In the superliner that I drove w/ 12 speed it is almost impossible to grab 11th(5th direct) gear with out grinding at least a little.

    #12 OFFLINE   bulldog man

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    Posted 30 May 2008 - 12:21 PM

    Ya the 12spd mack tranny really does have best of both worlds in speed it is a great all around tranny it will ceep & also will run out there w/ the Kenny's & Pete's Also


    & To me the best part is using the stick while raising a dumpbed just like the ole 2 Stick 6 spd trannys


    We had a 88 RW713 Superdog w/a 450 E9 Mack coupled to a 12spd tranny 14k f/a & 44k r/a on double frame man that was 1 sweet tractor for pulling grain, lowboy, dump & log trailers with.



    Thats 1 of the :mack1:'s i miss




    later yall

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    Old Dog Is alive & doing well w/ new owner right here in the Millington,Tn Area !!! Thank you Lord for sending a fellow Mack Man to rescue my name sake & pride & joy Old Dog from the scrap yard in Memphis!! hopfully he will running again soon.


    #13 OFFLINE   Warpman89

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    Posted 31 May 2008 - 05:16 PM

    Oh I also forgot to tell you. In the superliner that I drove w/ 12 speed it is almost impossible to grab 11th(5th direct) gear with out grinding at least a little.



    my trick for that is to leave it in high and go from 4 high to 5 high, then put it in direct and rev slightly so it engages into 5 direct, it works for me and when you get the hang of it, it won't grind anymore

    i hope that makes sense...

    #14 OFFLINE   MackR797-W45Holmes

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    Posted 01 June 2008 - 01:53 AM

    my trick for that is to leave it in high and go from 4 high to 5 high, then put it in direct and rev slightly so it engages into 5 direct, it works for me and when you get the hang of it, it won't grind anymore

    i hope that makes sense...


    Yes this works for me also.

    Steve.

    #15 OFFLINE   Freightrain

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    Posted 02 June 2008 - 02:09 PM

    Kinda like a two stick, main stick up a gear, then rev it to get compound to catch up to UD.
    Larry

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    #16 OFFLINE   Lmackattack

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    Posted 02 June 2008 - 06:26 PM

    Kinda like a two stick, main stick up a gear, then rev it to get compound to catch up to UD.



    larry why not just make another you tube video for us LOL!!! only if you could have charge for vewing and copying your vid LOL!!!

    #17 OFFLINE   Lmackattack

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    Posted 02 June 2008 - 06:26 PM

    Kinda like a two stick, main stick up a gear, then rev it to get compound to catch up to UD.



    larry why not just make another you tube video for us LOL!!! only if you could have charge for vewing and copying your vid LOL!!!

    #18 OFFLINE   Freightrain

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    Posted 03 June 2008 - 02:19 PM

    I need to get up to Stan's and get my "test drive" in his Superliner. Then videotape it.......ya, that's it.

    (I'll look like a tru rookie in that thing...grind'n gears like a 14 yrs with his learners permit)
    I'm not sure how well I could drive a "ONE" stick tranny? LOL!!!!!
    Larry

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