GearheadGrrrl

The "Volvo" frame may not work as well for construction trucks. However, I finally got a chance to drive a CX with the "Volvo" frame at UPS this fall. I was impressed- the old CHs were great, but the "Volvo" frame is a big improvement with better ride and tighter turning radius. YMMV... BTW, got my retirement paperwork today- looks like my last day at UPS two weeks ago will be my last day trucking for a living. I got to spend that day in a Mack Vision- no way would I end my trucking career in anything but a Mack! The pension plan requires that I not work in the same field, but I can still drive a Mack for fun... Maybe I should start shopping for a Mack?

On of my fellow temps at the Minneapolis UPS Hub (All Mack!) maintains a concrete plant during the construction season. In 2006 he worked overtime like crazy all the way into november. This year he hasn't gotten any overtime and he may make the jump to UPS if a permanent position opens up.

I believe that's a NATO standard called the "DROPS" system that the British initiated. It's rather clever, and they can even pull a trailer with another module on it.

I believe 1900 RPM was the normal full power governor cutoff with that engine, with no load cutoff of about 2100 RPM. You can probably adjust the governed speed up a bit, but the 673 is only good for about 350 reliable horses so I wouldn't up the fuel rate too much. BTW, is that an aluminum frame I see?

I'm back temping again at the local UPS hub in Minneapolis. We have an all Mack fleet of tractors, ranging from 241xxx series '94 vintage CHs to 266xxx series CX Visions on the shared Mack/Volvo chassis. We had some Ford Louisvilles and International S Series of similar vintage, but they didn't stand up as well and have all been scrapped. I spend most of my time moving trailers around the yard with one of our Ottawa spotting tractors, but once in a while I get out on the road for a bit. I've grown to like the CH, but a few details still bug me about them, like the long handled turn signal lever/high beam switch you keep bumping with your knee when you go for the clutch. I'd driven a CX around the yard before, but last week I got to take one on the road for a whole shift. I was most pleased- the clutch is easier, the turn signal lever no longer competes with my knee for space, it turns tighter, and rides better. Visibility is much improved with the sloping hood, and it's even easier to properly place in your lane. Finally, Mack has built a conventional that is as comfortable and has as good an ergonomics as the old R model. Yesterday two rentals showed up, a Freightliner Century and an International 8600. I was going to try the Freightliner at first, my driving experience in the new cab Freighliner being limited to backing one in for a two week wonder who couldn't. Noting that the steering column was raked back in the now popular "gangbanger" style with no apparent adjustment, I abandoned the Frightliner for the International. My pre-trip inspection revealed an engine all but buried under the International's medium duty cab, but the ergonomics were actually pretty good. The 11 litre Cummins engine was a real disappointment though, barely able to power the accessories below 1300 RPM and shut down at 1800 with not a hint of governor overrun. With it's underdeveloped electronic controls first letting it darn near die on clutch engagment then surge ahead, one had to use way to many of the Fuller box's 10 gears just bobtailling. Both the CX and International had these "low bid" Fuller boxes, and their tiny gate made it a pain to select the middle gears in the pattern. The CHs have proper Maxitorque 9 speeds, and their spring loading of the wide gate makes it easy to find the gears. I've been spoiled by the 1000-1800 RPM operating range of the older CHs and the 1100-1950 RPM ranges of the Maxicruise engines in the newer Macks- I feel sorry for the driver stuck with Cummins, Cat, and Detroit's less flexible engines. BTW, I get over to the Eagan hub once in a while and it looks like they have at least one MH in the deadline- I'll have to stop and pay my respects before they're scrapped.

True, Macks have long been available with vendor components. However, starting with the CH Spicer assembled the whole chassis complete with their or other vendor axles and delivered it complete to the North Carolina assembly plant that built the CH. If you wanted a CH with proper Mack drive train, you were threatened with high upcharges and long delays in assembling your truck. A lot of formerly Mack customers then went on to the Peterbuilt, KW, or Freightliner dealer and never came back. Today, about the only thing left that's Mack on a Mack truck is the Mack axles and transmission if you can get them- otherwise it's as much an assembled truck as a Paccar product.

Why put in a 15 speed? Your ENDT675 puts out over 90% of peak power all the way from 1200 to 2100 RPMs. Thusly it works just fine with a wide ratio transmission like the Maxitorque TRL1075 or 1076. The close ratios of the 15 speed won't make your old Mack any faster, instead it'll just keep you busy shifting.

The Allison will out accellerate a manual transmission up to about 30 MPH, above that it's a wash. If your Maxitorque is working fine I'd stick with it, but if it needs replacing an Allison would be a good bet if you can find one at a reasonable price. Unfortunately HT series Allisons are expensive even used, and you'd have a coronary if you heard what they cost new. I drove a 300 horse Mack with an HT740 for several years, and never had it stall. But that was on highway and even though we ran at up to 80,000 pounds we never saw steeper than 8% grades. If you're running at lighter weights or don't drive up steeper grades an HT740 would work for you- otherwise you'll need the HT750 with the deep ratio first gear. Probably the cheapest way to get an HT740 is to buy a used Postal Service Mack besides the Allison you'll get a 300 horse E7 Mack engine and a lot of other useful parts in the deal.

Was that picture taken at a Postal Service facility- the trailer in the background (300021) should be a '97 vintage FRP 33 footer.

Sounds like a good truck, assuming a single rear axle will give enough capacity for the load you're carrying.

I note a press release in there announcing that Volvo will be offering their failed "replacement" for the Autocar trucks, the VHD, with a short sleeper. No mention of the Mack Pinacle and Rawhide which are already available with the optional Granite frame and Mack's whole assemblage of sleepers from small to wow! It's nice to see Volvo taking my advice and offering a sleeper cab on/off road truck for the booming oil field market, but they should be promoting the Macks which offer the Maxitorque/Maxidyne powertrain and double reduction axles that can't be had at any price on a Volvo.

You might want to remember that even with a car/light truck engine a B model will weight at least 8,000 pounds. If you want decent fuel mileage and performance at least a 6 liter diesel engine would be a good idea.

I'll be in eastern Wisconsin during the Walcott show, but I'll be making a lot of trips to Iowa for the rest of the year. I could send you an e-mail when I'm headed down that way with my pickup. BTW, I saw a F model Mack Western for sale that would look great in your collection the other day near Farmington, Minnesota. The cab was pretty badly rusted though, it had the "bustle back" sleeper so it's probably an early 70s model. The frame looked good though, and it had Mack axles and bogie on spoke wheels. Engine was a Maxidyne with 5 speed Maxitorque transmission. It was last licensed in 2006, even had the keys in the ignition! Also saw an F model hooked to a grain trailer near Mason City- Mack better keep supplying parts for these old trucks...

Those are some most impressive models- if you hadn't said they were models we'd have thought they were real! BTW, if anyone is looking for a steel nose RD in 1:1 scale, I saw one parked alongside the road in Geneva, Minnesota with a for sale sign on it. I didn't see any rust on the cab, and it looked to be an RD600 with at least 44k rears.

From where to were in Minnesota and Iowa? The biggest thing I have is a Ford Ranger but I live in Minnesota and might be able to help.

I agree- it's easier to change two sets of differential gears. Auxiliary trannies may add a certain exoticness to a truck, but there are good reasons you don't see many new trucks built with them anymore. To add an auxilairy you need to add two new driveshafts, mounts, linkage, and maybe move some center bearings and crossmembers around. It's much easier to send the diffs off to be rebuilt with your choice of ratios.

I agree- upshifting on an uphill is the Maxidyne's weak point. Turning the governor up to 2100 or so shouldn't hurt the engine, won't hurt fuel economy unless you cruise it above 1800, and will make for a marvelously flexible engine.

I'm not disputing that they work well in a highway application, but I can say for sure that in a dump truck a 1750 RPM limit just doesn't cut it.

My first experience with an E9 was when I made the mistake of getting into the Monfort (left) lane next to one stopped at a red light. The E9 was pulling a fully loaded flatbed, while my 6V92TT pulled but a light load of bread. I managed to stay with him for the first couple gears... Then he took off and I had to retreat in shame to the McLean's (right) lane.

The EM7 is a Maxidyne engine, and those that came with a wide ratio Maxitorque transmission like yours usually had the governor set for around 2100 RPM with peak torque around 1200 RPM. There was a rarer reduced RPM Maxidyne with the governor set for around 1800 RPM and peak torque at 1020 RPM. These were primarily installed in fleet trucks and UPS probably had hundreds of them, but a vocational truck usually came with the regular 2100 RPM Maxidyne. If your truck has the reduced RPM Maxidyne you can probably set the governor up, which will give you more flexibility but will cost some in fuel if you run it continuously at the higher RPM. Most Mack engines give the best full load fuel economy around 1500 RPM, and cruising them above 1800 RPM wastes a lot of fuel. The low RPM Maxidyne was developed so UPS and other fleets could save on fuel by cruising at 1600 instead of 2000 RPM at 65. The low RPM Maxidyne in an MH was a sweet combination- you could lug down to 40 mph in top gear, yet cruise at 65.

Amen! Even though the Granite vocational model is Mack's best seller, the Pinnacle has plenty to recommend it. For starters, you can have a Pinnacle, even with a sleeper, built on the same heavy duty frame as the Granite. In fact, you could spec a Pinnacle as an over the road tractor pre-speced with that heavy duty frame, 44k rears, 14.6k front axle, and an 8LL transmission all ready to convert to a dump truck when it's retired from over the road service. You can also spec a Pinnacle with the Mack exclusive 6 speed Maxitorque for easier urban driving. Topping it all off is a cab that's been out for nearly 20 years now and you still can't find a rusty or rattly one, with the option of a removable sleeper to boost resale value.

Even with a 350 horse motor, at US wide maximum weights (80,000 pounds) you've only got about 10 horses/metric ton. That will produce good performance for a truck, bit might still take 1/2 mile to reach 60 MPH. As for drivetrain losses, the standard figure I've read is about 2% for every gear reduction. That explains why many fleets use a direct drive transmission with single drive. BTW, while the double reduction Mack axles theoretically have more friction, in practice it works out about the same because their high input gives better driveline alignment and thus less friction in the U joints. As for direct drive, with engines putting our over 1500 lbs./ft. of torque the drivelines won't last, so overdrives have become a neccessity.

20,000 Ohms! It's a good thing the fuel system can supply only so much fuel, otherwise you might be able to turn that engine to scrap metal. 400 horses is quite enough- many folks on this list are making a living with 237, 285, and 300 horse engines.

Mackdaddy, as a Volvo stockholder let me apologize for the parent company's arrogance. The MP10 has been available in North American Volvos for over a year now, those Volvos use the same frame as a CH, so it should be no problem to fit a CH cab on top and Mack axles. But Noooo... Volvo is keeping the "good stuff" for themselves and keeping Mack out of booming markets like eastern europe. Despite Volvo's attempt at hobbling the bulldog, a Mack is still the best truck for your job. The spec sheets for a lot of Mack models have mysteriously disappeared from their web page again, but last I remember the Pinacle was available with the Granite chassis' 300 mm. tall frame rails in thicknessess up to 9 mm. Throw in Mack axles, and you've got a heavy hauler with a sleeper option that most competitors can't match. As for engines, the MP8 is more than a match for anything short of the most juiced up 15 litres from Cummins or Cat. Mack has the edge in transmissions too, with exclusive triple countershaft gearboxes including an 8 speed with double lows and 13 and 18 speeds. And of course nobody else offers double reduction rear axles in a highway truck. If you want a short sleeper, Mack offers one and with a sliding 5th wheel you should be legal with that 50 foot lowboy in 65 feet. If the price is in the same ballpark as KW et al, I'd stick with Mack.

The Postal Service Macks can often be found on eBay and truckpaper.com, search under "Mack" and "MR688". The Mack engine block was the same size for decades, but the accessories mounted to the engines vary. Thusly I'd eyeball and measure pretty closely before buying an engine, and you'll need to check your rear axle gearing and how that will affect top speed, etc.. You'll also need to look into driveshaft compatability, changing to negative ground, etc..