What is the shift pattern for a 12 speed tractor trailer?

by Tyler
(Auburn, WA)

I might be getting a job soon and the guy told me that they had 12 speed trucks. I have only been trained on 9 and 10 speeds. How difficult is it to shift a 12 speed in comparison? I know that 13 speeds can be shifted like 9 speeds for the most part. Any info would be greatly appreciated

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Jan 02, 2015
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Mack 12 speed NEW
by: Anonymous

The 12 speed is a animal of all it's own.

Jan 02, 2015
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Mack 12 speed NEW
by: Anonymous

The 12 speed is a animal of all it's own.

Jan 27, 2012
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12 SPEED MACKS BACK IN MID 1985
by: Anonymous

I HAD A NEW 1985 MACK WITH 12 FORWARD GEARS AND 6 REVERSE GEARS. THERE WERE 2 STICK SHIFTS . ONE FOR LOW AND DIRECT. THE OTHER HAD 5 POSITIONS WITH A DIRECT TO OVER RANGE SELECTOR WITH REVERSE AND NEUTRAL.

TO GO THRU ALL 12 FORWARD GEARS YOU PLACED THE SHIFTER ON LOW POSITION. THEN 2ND SHIFTER IN 1ST GEAR SELECTION WITH SPLITTER SWITCH IN DIRECT.

FOR 2ND YOU JUST MOVE SPLITTER TO OVER RANGE.

FOR 3RD MOVE SHIFTER FROM LOW TO DIRECT THEN MOVE SPLITTER TO DIRECT.

4TH JUST MOVE SPLITTER TO OVER.

5TH MOVE SHIFTER TO 2ND POSITION AND SPLITTER TO DIRECT.

6TH GEAR MOVE SPLITTER TO OVER.

7TH MOVE SHIFTER TO 3RD POSITION AND SPLITTER TO DIRECT.

CONTINUE FOR NEXT 5 GEARS.

TO USE REVERSE PLACE SPLITTER SWITCH IN REVERSE POSITION. THEN YOU USE SHIFTER TO GET 6 SPEEDS. GREAT TRANNY.

Sep 07, 2011
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12 Speed Possible.
by: Anonymous

Check to see if it is a Mack Truck. On some models they are set up like a Super 10, plus 2 reverse gears (they are apparently counting them) and it equals 12.

Feb 08, 2011
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lots of transmissions
by: Anonymous

Well as stated before there really isn't a speed unless he has some really old trucks. Back when I first started driving in the 70's we had two stick transmissions some were 3&4 combos and other were what they called 4x4's and 4x5's. what you here take the first number and multiply the 2nd number and it will give you total number gears.

As far I know these transmissions are not being made any longer, but as newer transmissions my last truck had what is known as a 21 double over which again I don't think they make any longer.
So there you have a short lessen on transmissions I hope it helps.
Mushroom!!!

Dec 05, 2010
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A 12 speed ?
by: Jimmy

I've never heard of a 12 speed. He's probably referring to a 13 speed, which is a 12 speed not including reverse gear. Look on You-Tube for various transmissions and how to shift. Jimmy

Dec 05, 2010
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