12 speed 2 stick question...

[Outbehindthebarn]

 

I have an 1980 Mack with 12 speed, the shift levers are not in alignment with one another (the 'compound'(?) stick is about 6 inches forward).... I thought that was how 2 stick 12 speeds were arranged... then I see the 1982 spec'd the same as mine, but the shift levers were aligned like I've seen most 6 speeds. Any reason for this? 

 

When was the 12 speed introduced anyway?

 

[Yoos Brothers Construction]

I believe the 12spd came out around 1971/72 and ended in 1999. As for the sticks being in different spots Mack made 12spds with 2 different gear shift locations. Generally R models and DMs shift out of the front tranny case. Some Superliners, some R700s, DM800's, RD800s, and CLs shift out of the middle tranny case because of the cab being back further. They had different shifting rails but the ones like in the Superliners could still except the gear shift for extended range in the front case as well as the middle case just because of the way the fork was made. I have seen several exceptions to the rule so maybe yours falls under that category. I can post some pictures of the 2 different spots later to show the difference. Hopefully this will help.

 

Thanks, Josh 

[Outbehindthebarn]

15 minutes ago, Yoos Brothers Construction said:

I believe the 12spd came out around 1971/72 and ended in 1999. As for the sticks being in different spots Mack made 12spds with 2 different gear shift locations. Generally R models and DMs shift out of the front tranny case. Some Superliners, some R700s, DM800's, RD800s, and CLs shift out of the middle tranny case because of the cab being back further. They had different shifting rails but the ones like in the Superliners could still except the gear shift for extended range in the front case as well as the middle case just because of the way the fork was made. I have seen several exceptions to the rule so maybe yours falls under that category. I can post some pictures of the 2 different spots later to show the difference. Hopefully this will help.

 

Thanks, Josh 

Good info there Josh.... My truck was originally spec'd with a  six speed and the 1005 V8, but someone said along the line that the V8 was too much for a six speed (according to build sheet) and it was changed mid-production to the 12. The carpet was even butchered a little to make a hole where there shouldn't have been one. The fore shifter actually kind of interferes with the heater box. It just seemed like kind of a hatchet job. 

[m16ty]

I had a '85 R that had a Mack 10 speed in it. It started giving trouble so I put a 12 speed out of a Superliner in it. I ended up having to raise the back of the cab 1" to get the 12 speed to fit. I don't know why this was unless it had something to do with the trans coming out of a Superliner.