Shifting a Mack 12 speed

That's not a switch, it's just a protrusion in the aluminum housing. It lines up when the switch is in neutral, I suppose so you can tell by feel where neutral is, or go past it and hit reverse while going down the road.

 

How old is that rat trap you're driving? I respect a guy that will drive a hoopty, no questions asked. Judging from the small glimpse that pic provided- that's a HOOPTY!!! Lol

 

If your mt just go 1-2-3-4 without splitting. Split 4-5 as needed .....,

To split move splitter and let off gas.....

It's been a long time, but I remember hating that transmission.

 

I will bookmark this thread in case I ever get into a customer's truck that happens to be a Mack 12.

 

The Mack RD822sx in my avatar has a 12 speed.

I will caution you, it's not a very smooth shifting trans, especially for the inexperienced. What truck and what engine is it?

Don't even fool with the deep reduction during your road test. I'd probably not fool with splitting if empty. Just make sure your shifts are slow if not splitting, you can't shift fast without splitting.

Once you get some experience, you can try to hit all 12 from a stop. It's a little tricky going from deep reduction to direct while on the move.