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Mack 12 Speed


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Most all the trucks I ever drove had Fuller 13 speeds.  But I'm intrigued by the Mack 12 speed transmission.  I've watched several videos online showing how they work so I think I generally understand it.  Could anyone offer a comparison between driving the 13 speed and the 12 speed Mack?  I've heard some people say the 12 speed is a "love-it-or-hate-it" transmission.  Why is that?  And I've heard people say that if you're used to a 13 speed you'll have trouble adjusting to the 12 speed Mack.  Any truth to these rumors?  I've always heard good things about the Mack transmissions.  Would love to try one sometime.  Hopefully someday I'll get a chance.  

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Splitter boxes like the Mack 12 speed simply make sense... Even if you're using every gear, you're only moving the lever for half the shifts. Splitter boxes also make it easier to skip shift when running light- For example, with an 8V-71 hauling bread with a Spicer 10 speed splitter box I'd start in 1st or even 2nd high and go up in full gears, only splitting in top gear (5th).

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I personally find the Mack 12 speed to be a lot noisier. My old mans one has a whine once it gets a bit higher in speed. Also a bit more noise when changing. 

Not as many gears as your 13 speed. Definitely try it if you get a chance. 

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13 hours ago, mrsmackpaul said:

The road ranger you have to shift the stick for every change. Macks you don't.

I have never had any luck driving a Mack with out a clutch. The Road Ranger is easier to shift not using a clutch at least I find it is.

Paul

Hmmm.  On all the Roadranger 13 speeds I drove you really only used 12 of the gears.  1st was basically granny low so you'd normally always start in 2nd.  But you did not move the shifter for each shift.  You move the shifter for the first 4 gears then pop it into high range and run through the 4 positions again.  However in high range you could split each gear with the thumb switch (giving a total of 12 gears).  I never used the clutch except to start/stop on the Roadrangers.  

Do you have to clutch each shift on a Mack 12 speed?!  Uuugh.  Hope that's not the case.  That would be a major turn-off.

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32 minutes ago, sodly said:

Hmmm.  On all the Roadranger 13 speeds I drove you really only used 12 of the gears.  1st was basically granny low so you'd normally always start in 2nd.  But you did not move the shifter for each shift.  You move the shifter for the first 4 gears then pop it into high range and run through the 4 positions again.  However in high range you could split each gear with the thumb switch (giving a total of 12 gears).  I never used the clutch except to start/stop on the Roadrangers.  

Do you have to clutch each shift on a Mack 12 speed?!  Uuugh.  Hope that's not the case.  That would be a major turn-off.

No. If you have shifted a mack 5 speed you can shift a 12 speed.

Edited by terry
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I have two 12 speeds, and to be honest, It isn't my favorite.  You can't preselect in the lower gears. You can't get into fifth gear without a little crunch from the air shift. I don't use the clutch.   Look at it like a five speed with a two speed rear.  You can (but don't have to) split every gear.  In my opinion, the 18 speed is hands down the best transmission you can put in a truck.  The 13 speed is right behind it.  The biggest benefit to a 12 speed, is that you have 5 speed in reverse.  Another huge drawback is not many drivers have 12 speed experience, I don't like teaching people to drive in my trucks. 

 

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7 hours ago, sodly said:

Hmmm.  On all the Roadranger 13 speeds I drove you really only used 12 of the gears.  1st was basically granny low so you'd normally always start in 2nd.  But you did not move the shifter for each shift.  You move the shifter for the first 4 gears then pop it into high range and run through the 4 positions again.  However in high range you could split each gear with the thumb switch (giving a total of 12 gears).  I never used the clutch except to start/stop on the Roadrangers.  

Do you have to clutch each shift on a Mack 12 speed?!  Uuugh.  Hope that's not the case.  That would be a major turn-off.

every road ranger I have driven wont shift until the gear stick passes thru the neutral gate in the box except for deep reduction can be shifted on the go with just a flick of the throttle and the switch  

I never have used all 12 speeds in a the Mack most times maybe 5 or 6 speeds only unless the weight is getting up to over 40 tons then I may split 4 th and 5 th once you go above 60 tons I find 3rd 4th and 5th need to be split even taking off on a steep hill with big weights lift off in deep reduction then low 1, 2, 3 and split after that  

But with a Mack motor even a cool powered Thermodyne they pull like a train so I find a lot of the time I will drive them just like a Maxidyne fine 

Paul

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3 hours ago, harrybarbon said:

Please what is the difference between the Mack 10 speed overdrive and the 12 speed overdrive boxes - is it only the 2 deep reduction gears?

What difference is there between an E6 - 350 with a 12 speed overdrive versus a E6 - 350 with the 10 speed overdrive? 

If you are talking both 107 series trannys, they are the same except the 12 spd. has two lower creeper gears.    terry

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21 hours ago, GOOG said:

I have two 12 speeds, and to be honest, It isn't my favorite.  You can't preselect in the lower gears. You can't get into fifth gear without a little crunch from the air shift. I don't use the clutch.   

 

Yikes!  You can't pre-select the thumb switch on a 12 speed?  I figured surely you could... just like on a RR 13.

I'm not up on Mack 13 speeds.  Hoping to keep this conversation focused on the Mack 12 vs. the Fuller RR 13.  

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In my dads, when you go from direct to hi is fine. But when you preselect direct before shifting the stick it will sometimes jump back down a gear. This mainly happens in 1st in my dads. 

In other gears it preselects fine. 

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I hit the air shifter after I make neutral, going from 1st to 2nd.  I usually preselect going from 2nd to 3rd. If you keep a little pressure on the shifter it works fine and will air shift as you shift manually.  If you don't keep enough pressure on the lever the air shifter will down shift about as violent as an earthquake.  The other shifts are much easier.  My 18 speed is effortless and easy.  A gear for every occasion.  There is no comparison.  I am going to swap the 12 in my Superliner for an 18 at some point in the future. 

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Here B the §wish do n sum gear lapp n

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Clikity .................................................ClikClikClik

 

2 problems

<1> the Dynatard hangs on n wont release all the time (fix: New relay fiited)

<2> The clutch is a bit grabby n wont slo the gears down when start n off (Solve problem: Clunk the gear lever into 1st The biggest meanest cog in the box to slo the gears down then grab the desired gear for lift off

 

cya

§wishy

 

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I have a 12 speed in my RS700L. Mine is the older one I have a separate stick for Low Low not the air shift on dash. We have a couple RD's with 8LL. Had a CL with 18 speed once. Several 2 stick 6 speeds. A triplex. A quad box. Another R model with a 12 speed with the air shift on the dash for low. A superliner with a Mack 1070 10 speed (same as 12 speed without low). A value liner with a 13 speed road ranger. 

Having drove pretty much every trans you can get in a Mack except the brand new ones. I personally love my 12 speed. I don't have to shift a lot. Multi speed reverse is great. I love being able to set my PTO speed how I want for running dump trailer or lowboy. I honestly don't know why Mack didn't sell more of them. 

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