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Found another Mack in the Weeds


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Hello everyone,  Hope you got your junk put away...the white stuff is a comin here in the Northeast.  I had a guy stop in the shop last week and informed me that he has a 1958ish B Model with a diesel and triplex sitting in the weeds. Frame was cut at the front spring shackle and the outer fenders were gone but the rest was there. I have not seen it in person yet, but the price sounded real good. Soooo.  I want to know what you think about a triplex behind a 6v53 Dripoit.  Is it even possible to bolt it up.  The Detroit is a SAE2 and I have no idea what the Triplex is...PS.  Don't be haten

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I've got a 6V53T in my B85F.  Allison automatic behind it however.  Fantastic motor as a replacement for this sized rig.  Pretty sure the triplex is a single countershaft transmission.  Not sure it would handle the torque of the 6v53.  I mean I think you'd be fine with it as a hobby truck, but pulling a hill with any sort of load I think would be a risk.  Upside though is much of the issues mating a triplex to a more modern engine (ie. 237) may be mitigated by the fact that the detroit is a high revving engine and the issues with the triplex is usually making sure you don't lug it at lower RPMS.

 

I could be wrong, just what I think I remember reading in the past and from limited experience.

Ed Smith

1957 B85F 1242 "The General Ike"

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I have got the engine install pretty well figured out and have been toying with the idea of what trans to use.  I have the original Fuller 5 speed that came off the Detroit and I have the little Duplex from the 401 Gas job.  I would love to keep 2 sticks but the Duplex would not enjoy the torque of the 6v53N.  Being the Triplex if from a diesel i thought it would be better suited for the Detroit...If I can make it fit.  According the build sheet it looks like its got a 6.20 rear axle and with 48" tire, 2500rpms and 1:1 in the transmission.  It should run 52mph.  If I push the Detroit to 2800 it should run about 57mph.  

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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.

Edited by doubleclutchinweasel

"Eagles may soar, but weasels don't get sucked into jet engines."

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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...

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"Eagles may soar, but weasels don't get sucked into jet engines."

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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.

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"Eagles may soar, but weasels don't get sucked into jet engines."

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Put the 2 stroke in there!! It's your truck, don't even concern yourself with what anybody thinks. The small duplex is probably a 67 series and it might not like the ride too well. The triplex will be either single over or double over which will help road speed. GO for it and keep us posted  

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