Well, I'm not entirely sure whether to post my latest acquisiion in the antique or modern subforum, as she kind of sits in between being a genuine classic (70s and earlier) and modern.
So, if the moderators see a need to shift my topic to another subforum please do.
Vicky is a 1989 DM686, ex-mixer chassis that I bought as of last week, clean title, running and driving (if a tad low on air pressure in the tires). I bought the Mack for the purpose of building a heavy spec local 4-axle tractor.
I run heavy haul through the hot months, largely within about 150 miles of Denver. We do a lot of jobsite to jobsite work, rather than dealer to dealer or manufacturer to dealer work.
My primary tractor is Suzie-Q, a 1990 W900B Kenworth with a 444 Cummins and factory 6x4 set of boxes. I love her to death, she's been an absolute sweetheart to me. She's grossed over 200,000lbs, and does it without question. She's got DS402 4.44 cogs out back, dragging weight isn't an issue.
That being said, Colorado allows pretty aggressive axle weights, and we get into some specialized work requiring high frame load on the power unit. I've pushed the DS Eatons as heavy as 62,000lbs (no lift or jeep) under limited circumstances, but, at this point I'd like to have a heavy spec for that sort of thing locally, while Suzie can run the big stuff when we get the 2-2-2 or 2-3-2 out to spread weight.
Vicky has a 20,000 steer and 54,000lb Mack rears on walking beam "suspension", a rather euphemistic way to describe Mack's walking beam suspension.
She's short, too. All of a 190in wheelbase.
I'm intending the strip the rest of the mixer gear and slip a 20,000lb lift under her, giving her a 94,000lb GVWR. With a four axle tractor, maximum legal load on the tractor is 90,000lbs with an annual oversize (20k on steer, 70k on three axle drive grouping). Sitting pretty on that one. Assuredly, some site or off-road moves we'll be throwing the axle weight limitations out the door, as well.
Vicky has a 1071A Mack 6spd. One of the things I was happiest about this truck having, as it gives me the nearly absurd 23:1 low hole.
I'm considering dropping a 1241D behind the 1071A, however. The truck does have the high torque rise E6 in it, however, I'm thinking, in mountain situations, when needing pull heavy grades, some ability to split the 6spd might be useful to me. Honestly, the 1241D would largely be used as a 3spd, primarily splitting between under and direct, and then gaining the OD gear for empty running in the auxiliary.
I'm wondering if anyone here has experience with adding an auxiliary behind a 6spd or 5spd Mack and if they feel the addition was worthwhile.
I don't want to swap to a different main, so to speak. The 23:1 low is ideal for extrmely heavy starts.
Other plans include Cozad ramps and pintle hitch out back, headache rack. She'll get some chrome, but not much. She'll be kept in form to do dirty work in nasty conditions. A single, short stack, chrome cap, polished tanks and diamond plate fenders are about the sum total of planned shiny things.
If you happen to know DM's well, feel free to add whatever knowledge you have. I bought the truck knowing the older mechanical Mack's tended to have bulletproof components, precisely what I want when I'm going to shove 45 tons onto the power unit. But, I can't say I know a great level of detail about Mack components. So, teach me what you know.
Troy.