GearheadGrrrl

The "uprate" to "400 HP" sounds fishy... 300 HP was the top rating for a Maxidyne 6 cylinder until I believe 2004, when Mack bumped the power up to 370 HP at governed speed and 405 HP peak. IIRC there were a bunch of other changes to the engines besides just a software update. As for operating range, a vocational truck like the RD would probably have the standard Maxidyne with an operating range from 1200 to 2100 RPM. If that's what you have, downshift at 1200 and upshift at 2100. This assumes they didn't totally screw up the power curve with their "uprate". There's a slight chance you've got a low RPM maxidyne with an operating range from 1020 to 1800 RPM, but those were mostly installed in highway tractors.

Sounds to me like maybe ATHS is having financial problems and thinks that micromanaging the forum is the solution. The strategy is failing- The forum takeover has probably already cost them thousands in membership renewals. And to make matters worse, li'l ol' GearheadGrrrl justed popped back up on the ATHS forums!

Damn... I leave (LOL) ATHS and the whole place falls apart! Guess I'll have to go back and straighten 'em out...

Well, this "truck writer" wasn't all that impressed, and I said so on my www.GearheadGrrrl.com blog. They could get the same MPG or better with the MP7 Maxicruise and a Maxidyne manual transmission, and it'd last at least a million miles!

In a low mileage operation like you're probably in there's no reason a truck can't be safe and reliable for twenty years or more.

1980 sounds a bit early for a "300", it might be a 285 HP Maxidyne or 315 HP Thermodyne. Neither engine has given anyone much in the way of problems. Performance at 77k pounds should be adaquite, though crusing speed is more likely to be 65 than 85. And you're right about the radiator- better find out what a replacement will cost before buying the truck. Best of luck!

My neighbors got both an 8N and it's Ferguson twin, and he's got one or the other working most everyday.

You're right on the dividing line between the two- at 120k gcw the Granite's maximum 505 horses is just adaquite, but the Titans 605 horses will come with a price and weight penalty. The choice probably depends on how hilly an area you're trucking in, as 505 horses are probably enough on flat roads, though if you're trucking in the mountains 605 horses could significantly reduce your trip times.

Had enough of the heat and really old rich people down here in Naples... Headin' back to Minnesota tomorrow!

I'm heading back to Minnesota from Florida next week- Gettin' too hot down here! In Naples we've had highs in the 80s most every day, back at my place in southwest MN the temp is above freezing almost every day and almost no snow.

As for the KW T600s bodged into dumps in Florida, seen plenty of them. They can run 44,800 on a tandem in FL and 73,280 on four axles, so there's incentive to stretch and liner the frame on a road tractor and put super singles on the 12,000 pound rated steer axle so it can meet the tire width requirements to run at 73,280... The wheels sticking way outside the front fenders are a dead giveaway! You can also see where the took off the sleeper, etc.. Amazing the junk some folks will run! I've also seen a lot of short tandem end dump trailers pulled by single axle tractors- I imagine that with the lighter weight they have about the same payload as a 5 axle rig at 80,000 pounds.

I suspect they're canabalizing for parts- in a third world environment new parts are something they can't afford.

I"d be suspicious, unless the seller can show you some documentation that it came from the factory with the double frame and heavy axles. There are a lot of backyard bodgers who buy a road tractor, stretch and double the frame from the cab back, put on a camelback and float tires in the front, and try to pass it off as a heavy duty straight truck. When I see that kind of stuff on an aero truck like a KW T600 or Mack CX I know it's probably not OEM... Look this truck over VERY carefully!

Gee, when I worked for big brown they never gave me a uniform like that... Which at my age, was probably a good thing. The two wheeler ain't UPS issue either...

The EPA and DOT and Obama don't have much to do with it- outside of some parts of California, you can run an old Mack or whatever for as long as you wish. The real reason those Macks are getting imported is because too many trucker wannabes demand a long nose KW or Pete when an old Mack will do the job better.

Seems the rest of the world knows the value of a Mack better than american truckers do...

Interesting that these are all over the road rather than "vocational" trucks... Must be quite an embarressment for Volvo to see these customers choose Macks instead of Volvos!

Yup, I drove for USPS from 1993 to 2005. I loved the MR cabovers- great visibility, turn on a dime, and like you noted all the switches are right there where you can reach them. The air start is great too for a city truck that gets turned on and off all the time- USPS went back to electric starters with the 2006 order and ever since the mechanics have been busy jumpstarting them! As for the steps, watch out for the gap between the left side steps on the CHs though- a few drivers got hurt when they caught their foot too deep into the step which is open in the back. Also, the MR doesn't have much headroom and rides awful if the height setting on the air ride is off. Power wise, 300 HP is about right for city work, but if you do a lot of highway work at 80,000 pounds you might want a bit more. IIRC, both models have 3.90 gears, but the CH has an overdrive top gear in it's Allison that cuts the highway cruising RPMs down to a tolerable reading. What more can I say... The USPS trucks are built for urban trucking, and at the prices they're going for you can't go wrong!

Clearly some local variation in maintainence and dispatching... In Minneapolis they did no preventive engine rebuilds or main bearing "roll-ins", just ran them forever. Minneapolis got rid of the last of the CHs around 2007, I haven't seen anything but CXs on the road there.

On USPS Macks the hour meter reading is as important as the odometer- In many cases the trucks slog along in city traffic at average speeds of 20 MPH or so. Thus a USPS Mack with 500k mines may have covered the equilivent of a million highway miles. Like maintainence, this varies a lot with location- USPS drivers in Phoenix have told me of 300 mile round trip highway runs, while on Long Island they'll spend a whole shift creeping through city traffic at 10 MPH average. As for wasting money, those trucks have more than paid for themselves- remember they're 12 and 15 years old and we're probably double shifted for a decade or so. They were replaced in 2006, but I suspect the local USPS operations held on to them for spares.

Doesn't look like it's been shortened up any, might even be a fifth wheel under that box yet...

Nuthin' wrong with occassionally using a B model in good mechanical shape to do what it was designed to do, and a few folks on this site use their Bs to occassionally move lighter machinery or travel trailers. IIRC, the biggest engine offered in the B was 300 HP, and given the small radiator that's about all it could handle. As for weight capacity, IIRC the highest rated GCW was 76,800 pounds for tractors in the B7x range. So a B75 in good mechanical shape could probably handle that one but not both of those loaded trailers with a top speed of maybe 60, and hope you don't have to go over any mountains.

Junk + junk= More of the same! You'll need a dolly too, and at least a dozen new tires just for the trailers. And how many horses does your B75 have? With a long drawbar this combinbation would be good for around 100,000 pounds, and that requires around 400 horses just to keep up with the slow traffic. You'll need low gears too, to start 50 tons on an upgrade. B models are fine for show and pulling light trailers, but as working trucks they're pretty much obsolete- better to start with something like an R model for that.

Nice job of packaging all the back of cab stuff on the MRU.

I've seen a couple MHs that escaped the UPS whole.