doubleclutchinweasel

I'm kind of a Quad-freak! I grew up on the 18-speed double-overdrive Quadruplex. Have driven the 13-speed Triplex version. Same, without the LO-LO gears. Love those 2 boxes. Once you learn them, there truly is a gear for all occasions. Had 2-3 different shifting sequences, depending on the load and grade. Even developed a couple of different split-shifting styles. Again, depended on how big of a hurry you were in. To me, a Mack needs 2 sticks. The 15 RoadRanger I had in my '70 was a much more user-friendly box. But, I always felt a little bad that it didn't have the Quad in it. I hope to have another one someday.

Here was that engine... http://www.tyldenheritage.com.au/uploads/9/3/0/6/9306704/endt673c.pdf

Certain models of Triplexes and Quadruplexes (and there ARE different models...check your model number) were routinely used behind the ENDT-673C, which was rated at 250HP and 701 ft-lbs of torque. I have hauled 111,000# with that setup many, many times. So...

What kind of torque is that Detroit rated at? I see info suggesting 650-666. I think the n-plex boxes were used with engines rated up to 650 ft-lbs or so. If that's the case, it should be fine. Like with a Maxi, maybe keep the revs up...which shouldn't be an issue with the DD.

Sexy as socks on a rooster...

Here is some info about the later models, with REV on the compound stick. But, I can't find anything on the OD versions (1070). So, I don't know if they ever did one with OD AND REV both in the compound case. But, it seems possible. Again, the shift map plate would probably tell if it was a lo-hole or and OD setup. Here is the plate (off eBay) for a lo-hole model.

Here is some interesting info. Apparently, there WAS a setup with OD in the rear box. If this is the trans you have, then the OD on the compound stick can only be engaged when the main is in 5th. But, I don't know if these had REV on the compound. Doesn't sound like it. I am going to dig more into the "late" production boxes, and see what they have. Learn something new every day...

I love the look of that setup. Gotta have the Mack caps on them!

Couldn't zoom in far enough. Are those wheels stud- or hub-piloted? It's looking great!

Checking the front box in/out ratio would still be helpful. This would tell for sure if the front box had an overdrive gear in it. Some of these guys know a lot more than I do, but all the 2-stick Maxitorque auxiliary boxes I (personally) ever saw had a "lo" and a "dir". Never saw one with an OD in the auxiliary. I would suspect that there is only one set of reduction gears in the auxiliary (for lo), and the "dir" is just locked shaft-to-shaft. And, of course, the reverse set would be in there. If the aux is "dir", the sliding dog clutches would just key the shafts together. If there is an OD in there, then I would suspect the "lo" would be locked shaft-to-shaft, and the "od" would engage the overdrive gears. What did it say on the shift plate? LO and DIR? Or DIR and OD?

EB is what I was thinking. Here's a pic of a Jacobs piece.

Some tire manufacturers recommend a little less air pressure when running duals. This is because, due to uneven wear or the shape of the road, one tire can wind up with more weight on it than the other. Having a little less air pressure in them allows for some natural compensation between the two tires. This is also why the weight rating on a set of duals is sometimes (always?) a little less than double that of a single. At least that is how one of the big tire manufacturer's engineers explained it to me. Even the original door stickers on the older trucks called for a little less air in the duals than in the steers. You made get varying opinions on this.

Nice pair.

"Alaska Passage" - 1959. B-models.

Then I would definitely see if I could use the "new" rear box on the "old" front box. Since reverse is in the rear box, the front box is probably fine. Of course, I would like to hear from JoJo or one of the other pros about any issues one might encounter first.

I, too, thought the auxiliary was just low and direct. I always thought the OD was in the main box. In the "old" days, a "0" on the end of the model number indicated that 5th was overdrive. I don''t know how the later stuff was numbered. But, a TRXL-107 would have been direct, and a TRXL-1070 would have been overdrive, for example. Don't pay any attention to the exact numbers, as I may have them wrong. But, the "0" was the key...at least, it was at one time in history. Was yours a two-stick 6-speed? Or did it use air on the auxiliary? If it is the 2-stick, and the reverse is on the compound stick, I wonder if the "new" auxiliary would mate to the "old" main. Just thinking out loud.

That's what she said...

I have had the interior of hydraulic brake lines come apart myself, and they tended to act like a check valve in the line. You could apply the brakes, but they would not release. This is not unique to antique stuff. Had to replace both lines on the front of the wife's '05 Chrysler 300C for the same problem. Those were easy to diagnose, as it used twin-piston calipers on the front. Could push EITHER piston in easily, but it was almost impossible to push BOTH of them in. So, that narrowed it down pretty quickly. Really does sound like a rubber line issue.

Yep. That's it. That's where it was sitting when I was drooling over it. Really a beautiful job. And, with that Mack sheet metal perched high atop that Pete frame, it was an impressive site. You know you did great work when 90% of the folks that saw it had no idea what they were looking at. Looked "factory", which is a huge accomplishment in my opinion.

So, I guess that WAS the one I saw in Knoxville a few years back.

Why the razor blade, Train? Not thinkin' of slittin' your wrist, are you?

The problem you get into with multiple boxes is that some of the gears are duplicates. And, if you're not careful, you end up doing a shift that isn't really necessary. I like the looks of those 2 that appear to be factory 3-stick setups. From what I can see, they both look like Duplex transmissions with what is essentially the auxiliary section of a Triplex stuck behind it. Pretty awesome. In reality, the 13-speed double-over Triplex and the 18-speed double-over Quadruplex don't leave too many holes in the pattern! Like Freightrain said, the best use of the third stick is to add a lower and higher gear at the ends of the range. Most of the ones in the middle won't get used regularly. Like he said, they are pretty much redundant ratios. But, the extra low and the extra overdrive could really come in handy...depending on what the front box is. Still, the more sticks, the better! I think 2 should be mandatory on a Mack. The third one just makes it that much cooler. I drove a 9-speed Unishift once. Frankly, I preferred the 2-stick Duplex version. Not too much left to chance when you have an actual stick to stir those cogs!

I think I only ever personally saw one lose a turbo. Not sure what the cause was. I don't think there was a major issue with them.

Man, that's a great starting point. Excellent shape. Have fun with it.

Very cool, and a true classic.