doubleclutchinweasel

Agree completely. For a hobby truck, any of the Du- Tri- Quadru-plex boxes would be fine, even behind the 350. But, at the same time, a 5- or 6-speed would probably be fine for a bobtail ride, too. There is still plenty of torque in that 350 to drag it around, even without keeping the RPMs in the sweet spot. Bobtailing my R600 with the 250 Thermodyne and the 15-speed RoadRanger, I usually only used 4th, 6th, 8th, and 10th. It's be different if you had 80,000# behind it.

From what I have researched in the past few minutes, I think you are 100% right. The difference seems to be in how the deep reduction is operated (air or stick). I'm just not sure what LTK was wanting to know. Maybe I read too much into his question!

Maybe you need this...

So, again... Are you looking for something with NO air at all? Or were just just wondering about the shift pattern?

Actually, it looks like it also had an air shift portion on it. So, are you looking for a 12-speed with ONLY 2 sticks, or a 12-speed that ALSO has 2 sticks? LOL!

Well there you go! Learn something new on here every day! Thanks, 'Joe!

I don't know of an honest-to-goodness 12-speed 2-stick. But then again, most of my experience is with the "old" (Duplex/Triplex/Quadruplex) stuff. I have seen certain versions of the (overdrive 18-speed) 5 X 4 box called a "14-speed" before. And the overdrive versions of the 5 X 3 units were called "13-speed". But, the only versions of the "real" 12-speed I ever saw were air shifted. You have a knack for coming up with intriguing questions, don't you! I'll be curious to see what comes of this one.

Lots of guys on here with near-original B-models. I'm sure some of them will be able to get you some detail shots. Not sure about that notch in the frame where the steering box is...

You said a mouthful right there...

Spoked wheels definitely are easier to change on the side of the road with hand tools. No doubt. A spare spoke rim and tire is also lighter than a disc. Spokes can be more difficult to get true, though. Takes a little finesse. And I have heard stories of people twisting the rims on the spokes when heavily loaded. But, I never saw that in person. But, he's right. Somebody will probably be interested in those (especially the front) because of the disc wheel setup. Somebody on here every few days looking for hubs to convert one from spokes to discs. Not sure if he has hub-piloted or stud-piloted. Me, I'm still a pretty big fan of spokes! Just a stubborn old man, I suppose! Part of what made a Mack a Mack back in the day. To each his own...

Here was a flyer on the 673E, 180 HP version...

The 180s were very common, from what I remember.

Need more new pics! The things you spot on the road are WAY more interesting than the things I see around here.

The numbers stamped on the case could be the engine model. The first part on mine was "T673C". That identified the engine as an ENDT-673-C, which is pretty descriptive. Not sure if the stamping "rules" were the same back then, but it might be a good place to start. I SHOULD remember where the tag was on that one, but I just can't seem to remember. There were a few tags on it (valve clearance, etc.). Also tags on the pump. For some reason, I was thinking the H.P. was listed on a tag which was attached to the engine, not the pump. But, I could be wrong. And, like Larry said, pictures might be helpful.

Those twin-stick transmissions COULD be automatic. I know because my Dad drove one. He'd let off the throttle and I'd shift the transmission! There you go...automatic! Well, at least from his viewpoint! LOL! That's how I learned to shift one. Probably started when I was 4 or 5. Would give anything I have to re-live that right now...

Not sure on those later Maxidynes. But, on the originals (1960s vintage) there were LOTS of different internal parts. There were several discussions on here a long time ago about those older versions and what it took to convert from one Thermodyne to Maxidyne. It was pretty involved. I'm sure some of the Brain Trust will be able to help guide you on these newer engines.

If your biggest complaint about going fishing is that "There's always some sombitch that actually wants to fish"...

To quote my Dad, "Stay ahead of the truck." In other words, have it in the right gear for the next situation BEFORE you get there. And, like everybody said, don't leave both sticks in neutral. You'll get the hang of it. And remember, there is no law that says you have to split every gear every time! I rarely had to use them all. Only when I was really heavy did I need to split every gear. To be honest, you sometimes did it just to show off around the shop! Really looked impressive when you missed one! LOL!

Got ya. Sorry!

Is there a number stamped on the accessory drive case on the engine?

Could be a plate on either the engine or the fuel pump itself that lists HP. I'll try to find an example.

Like he said, the steps are BIG on a those boxes. Remember, the steps are a certain percentage drop, not a fixed RPM drop. So, if you shift at lower RPMs, the steps appear smaller (same percentage, smaller RPM difference. Those engines pull hard at lower RPMs also. I used to keep the revs fairly low through 4th. Then wind 4th pretty high, drop into neutral, take a nap, then drop it into 5th! Downshift only when the RPMs pull down to about 12-1300. Don't try to downshift at 17-1800 like we did with the compound stick on the Quadruplex boxes. Big steps! Big, wide steps! If the revs are, say 2/3 of what they were before an upshift, the equivalent downshift would be 3/2 the revs. So, if the revs drop from 2100 to 1400 on an upshift, then you have to pull down to 1400 before downshifting and rev it all the way to 2100 to get it to match up on the downshift. You'll get the hang of it. I am very curious about the RPM/MPH that 67' asked about. That OD trans should do more than that unless something (tach, speedo) is off calibration, or the rear gears are insanely low.