I looking at buying a 1980 Mack dump truck. Its a gold dog truck, and that is about all I know at this point. It has the twin stick transmission, and no shifting pattern on the dash/knobs. How do these sticks shift?
On the way up don't shift the main until your done shifting the auxiliary.
Is it an auxilliary transmission, or more likely, a 6 speed Mack?
The seller called it a 6-speed. I will not see the truck for a couple of weeks
https://www.ebay.com/p/934482848?ii...MI4LOT24zp6QIV2CCtBh0_ng75EAQYASABEgIskfD_BwE
I would call it "Main" and "HLR". Put the main in first and HLR in L. Then shift HLR to H. Then upshift the main like any 5 speed. When you need reverse, put main in first, HLR in R. Edit: "H" is actually direct. I haven't driven one since 1982. Makes sense that mack would put reverse in the compound box since the main is a triple coutershaft tranny.
It will be nice if it has some sort of engine brake. There is big gap between gears on those Mack 5 speeds, and it seems like it takes forever for the engine speed to drop enough to grab the next gear without something to help. When loaded, it would take so long and so much road speed lost, I would just have to go back to where I was and try again.
WoW...Been a long time since I drove one of those!! I can remember many times having both hands on the two gear shifts to try to get the timing right for shifts. Bring a friend along to help steer!
Basically a Five speed with an extra Lo gear. Is not a Tri or Quadra plex as in the Old Days Should be this pattern https://www.pgttruckparts.com/11MY4...-Extended-range-Pattern-p/2346-11my41ap28.htm
Those engines had a very wide power band and the oil nozzles under the pistons prevented damage caused by lugging.
Let it drag down to 11-1200 rpm a few times, Should load in and hold there just pound away, this is NOT a Cat or Cummins, leave her hammer.
The cars behind will just honk and pass.
This one would keep your mind sharp. No driving with a hang over
Air Shift 5x4, very clumsy.
Too bad the pattern plate designer did not sober up before drawing it.
Just like driving my L9000 with L10 Cummins.
Drove a 6 speed mack this week, guys around here and massachussets love them, Mack sold that transmission up into the early 2000's, one old timer told me why have all those gears when 6 gets the job done. Those transmissions shine on the jobsite, Low hole, 5 reverse gears, I was told you have to shift them on the Jake to keep from loosing road speed.
Our fleet didn't have them, but Macks back then had something called a "Dynatard Cam" as their Jake brake. If you ever adjust valve lash on them, make sure you do it like the manual says, using crankshaft positions on front pulley.
I drove a DM600 for a paving company with this transmission. Like the others have mentioned it's basically like driving a straight 5 speed transmission with a low range for off road. On steep hills you can get gear bound but on moderate inclines the torque of the old Mack will tug you along. The one I drove had a Mack Dynatard engine brake which help with quick shifting when necessary. There are 5 speeds in reverse and you can back up at close to 30mph, came in handy when you had to back in to the paver almost a mile.
My favorite-9 speed direct with a progressive 4 speed brownie.
I learned to drive a 6 spd mack when I was just a kid, really good stout setup having multiple reverse speeds is nice to
Friend of mine had a R series with a 12 yard dump on it, loved that variable Reverse when the cheap clients would tell him Spread it Fast and Thin, NOT a Problem, could scatter gravel like a burnout.