Independent front suspension, air-suspension all-round, an ultra-light forward-set alloy cab only 48″ long, power steering, a complex fabricated frame that was 50% lighter, and the lightest diesel engine: This was the recipe for the most technologically advanced semi truck tractor in the world in 1959. It could haul over a ton of extra payload capacity thanks to its light weight, it was highly efficient and was the most comfortable for its driver.
The DLR/DFR 8000 sprung from the same mindset that created the air-cooled rear-engine Corvair, the “rope-drive” Tempest, Buick’s Aluminum V8, turbocharged Cutlass Jetfire, the Turboglide, and a raft of other engineering firsts at GM in the years 1959-1962. None of these survived long-term, and most were gone within a couple of years, including these GMC DLR/DFR 8000s. Intended to vault the competition through sheer technical overkill, they were the result of the oft-deadly hubris that permeated GM. In this case, the failure of the DLR/DFR 8000 led to the GMC Truck division’s terminal decline in the heavy duty field.
The GMC “crackerbox” COE did survive longer, until 1969, but only because a very conventional dumbed-down version was rushed into production to replace the DLR/DFR 8000, not unlike the 1962 Chevy II and 1964 Tempest, Skylark and Cutlass. Turns out what American truckers really wanted was cheap, heavy, average, but good looking, just like American car buyers. How did GM not know this?
COE (Cab Over Engine) trucks became popular in the mid-late ’30s, like this 1937 GMC semi tractor. There were several advantages, the two biggest being better weight distribution and of course a shorter overall length. That become the dominant factor as the trucking industry expanded beyond regional reach and had to deal with an arcane hodge-podge of different length (and weight) regulations in an increasing number of states. The best solution was a short COE tractor to meet the regulations of the most stringent state(s) the truck would have to operate in. Of course there were other advantages too, in maneuverability in urban settings.
This ability to meet the various state restrictions was of particular importance to movers, which had to potentially be able to go to any state, and explain why long distance moving trucks almost invariably had COE tractors.
The truck industry prior to the mid-late ’60s was divided into two markets: the far West, and everything else. That’s because the West Coast had drastically more lenient length rules, so that long conventional trucks like this 1940s Peterbilt dominated there.
Even CEO trucks out West often didn’t take advantage of their space efficiency, like this long wheelbase early Freightliner.
As we shall see, GMC’s DLR/DFR 8000 was clearly targeted to the eastern market.
In the East, the White 3000, the first popular tilt-cab truck dominated the COE market in the ’50s.
International got in the tilt-cab COE market in 1953. It soon spawned other variants.
Meanwhile, GMC, which along with International had for decades been the two top selling medium/heavy-duty truck brands, only had an older style non-tilt COE, dubbed the “cannonball” for obvious reasons. GMC was risking seriously falling behind in what soon came to be the dominant style of semi tractor.
Both front and rear axles were suspended on air bags, resulting in a dramatic improvement in ride quality. The technology came straight from the buses. How many were actually sold with the air ride is another question. Not many, apparently.
But that just was a stop-gap at best. GM’s truck engineers went to work creating the ultimate COE highway tractor, one that would top the competition in every metric: weight, space efficiency, load capacity, and driver comfort. The “Tilt-Cab Cruiser” was first shown at the Chicago Auto Show in December 1958, and only as the cab-forward DLR8000.
This brochure from 1959 shows the DLR 8000 (left) with its aluminum cab in front of the axle and an ultra short 108″ wheelbase, which combined with its mere 48″ of cab length meant that longer trailers could be used in highly restricted states. It also shows the DFR 8000 (right) that was added later that year, which had its cab directly over the front axle, and also sat a bit higher too. According to the brochure, it was available in 108″ and 130″ wheelbase length. A very compact sleeper cab version was available in either configuration.
There’s very little detailed historical information about these trucks except from a few brochures and a few paragraphs at some forums. Even the definite book “GMC Heavy Duty Trucks 1927-1987” has precious little on them. GM press releases state that the DLR 8000 went into production in 1959, and the DFR 8000 was added sometime later in that year. This ad from 1959 only shows the DLR8000. And as we’ll see later, by 1960 a very conventional “crackerbox” with its cab over the axle like the DFR 8000 was added, which quickly became the only version offered.
The DLR 8000 was a clean sheet design from the frame up. Its frame was quite unusual, as instead of the usual riveted C-channel rails with cross members, it was designed some 50% lighter due to being fabricated from specially formed steel components and then welded together. The DLR’s frame (upper left) was quite distinct from the DFR’s frame (lower right) with its deep X member. This was all highly unusual and ambitious. For optimum weight distribution, the DLR came (only) with the inline Detroit Diesel 6-71, and the DFR was came with the new V6-71, since it was shorter and as such would not extend past the rear of the cab.
The very minimalist cab was fabricated mostly from aluminum, with fiberglass fenders and front grille. The sleeper cab added a mere 24″ length; it’s not visible here, but the 30″ wide mattress makes a jog behind the driver’s seat, narrowing it down to 22″.
The two different designs are more obvious here. The DLR’s X-braced frame (left) is even visible.
Here’s a good look at the independent front suspension. A traditional SLA (short arm/long arm) with ball joints.
More details on the front suspension and steering. Power steering was optional, something that was not at all common on big trucks back then, and for quite some time to come.
The standard 6-71 two-stroke diesel engines were rated at 189 gross/175 net hp @1800 rpm (DD diesels only sound like they’re revving fast because of being two strokes), and 577/553 ft.lb. of torque @1200rpm. The optional version with larger injectors had 210 hp. A five speed Spicer “synchromesh overdrive” transmission teamed with a two-speed Eaton rear axle. There was no twin rear axle version, and very few options. This was a very tightly specified truck for very specific applications.
Here’s the DLR specs. Unfortunately, there no weights given here, but I found it elsewhere: 9090 lbs.
The DFR was also available in a longer 130″ wheelbase.
Per its specs, the DLR 8000 was aimed at the fast growing regional truck freight companies. Given that the industry was still fully regulated (freight rates set by the ICC), the opportunity to haul an extra ton of freight could directly impact profitability.
These operators primarily covered the cities and industrial centers of the East and Midwest. Cross-country truck freight hauling was still quite unusual, and if so, the loads were typically interchanged at Denver or other key hubs with West Coast freight companies. But this was all changing quickly in the ’60s, with the growth of the interstate system. The DLR arrived just at the cusp of the great long haul trucking boom, and was too inflexible in its configuration.
Note that these testimonials from operators are all cab-forward DLR8000s. It’s pretty safe to assume that the DLR outsold the DFR by a substantial margin.
Moving companies were another target market, as maximum volume that could meet the shortest state restrictions was desirable. As was the air ride suspension, which movers adopted as soon as it became available, to protect delicate cargo from damage. GMC crackerboxes were seen hauling moving vans well into the ’80s and even later. This one has an added “pup” trailer, since it’s operating in length-lenient California.
And here’s one with a flatbed trailer.
A commenter left these two vintage photos of a couple of DFR8000 trucks that were in service for a company he worked for. The rear control arm for the air suspension is clearly visible, the hallmark of the air-suspension DLR/DFR.
And here’s the other photo. This truck was still in service in 1976 with over a million miles on it.
The technically advanced DLR8000 and DFR8000 were quickly supplanted and replaced by the DF 7000 (single rear axle)/DFW 7000 (tandem rear axle) trucks in 1960. They had the same basic cab as the DFR 8000, but were very much more conventional otherwise, and cheaper, too. The set-back front axle version (like the DLR) was not offered on this new series.
This over-the-axle tractor is what became commonly know as the GMC “crackerbox”. That nickname obviously reflects its utterly minimalist cab design, a curious contrast to what was coming out of GM’s styling studios at the time.
The frame was now a typical riveted C channel ladder affair, and suspensions were the usual harsh leaf springs, with a choice of two types of tandem axle suspensions (Page & Page Rocker or Hendrickson “walking beam”).
The air ride DLR/DFR8000 models were technically still available, but only through 1961, after which time they were dropped. A short run for a short truck.
Meanwhile the DF series quickly expanded, including the 7100 version with the new DD 8V-71 engine, making up to 318 hp. A 238 hp version of the 6-71 also became available in subsequent years, replacing the 6V-71, which had cooling issues in its early years.
Starting in 1965, the DF7000 series also offered the unloved Toro-Flow 4-cycle diesel as well as a gas engine, the 637 CID V8 version of the 60 degree GMC V6. Some folks claim the legendary 702 inch V12 “Twin Six” was available in the crackerbox, but that’s not actually the case. FWIW, the 637 V8 was just as powerful (275 hp), lighter and more efficient.
So why was the highly advanced DLR/DFR8000 so quickly abandoned? There’s only some anecdotal comments out there, but it’s easy to come to obvious conclusions. The independent front suspension apparently soon showed itself to be maintenance intensive. This was also the case with all the light/medium GMC/Chevy trucks that appeared in 1960 with their torsion bar IFS. We covered that subject here. Presumably the technology just wasn’t there yet to make HD truck IFS anywhere nearly as reliable as the traditional solid front axle, never mind the cost.
Although full air suspension was embraced enthusiastically by bus operators due to the big improvement in ride quality, truck operators were notorious penny-pinchers, and the additional cost was undoubtedly not justifiable. Who cared if the drivers had their internal organs deep-massaged eight hours per day? Air suspensions are extremely common now, almost universal in over-the-road semis.
In addition to those aspects, what undoubtedly undid the DLR/DFR8000 was its very narrowly-targeted one-size-fits-all concept, oriented specifically for medium/larger eastern freight haulers. It came only as a complete integrated package, with no wheelbase options, no tandem rear axles, and no drive line options. Other truck companies offered numerous versions, options and extensive customization. From some accounts, the DLR8000 sold poorly from day one, due to these reasons as well as its higher cost. That explains why GMC quickly rushed out the DF7000, a very conventional truck to suit the actual needs and preferences of its customers, not GM’s planners and engineers.
Although the DLR/DFR8000 had a short and unsuccessful life, the more conventional DF Series crackerboxes had a reasonably successful career on the highways of America, but it would never enjoy the dominant market share its predecessors did in previous decades.
They were tall and rather intimidating looking, so utilitarian and stark, and as such very easily identifiable. With the legendary 318 hp DD 8V-71, they were also considered to be about as powerful and fast as anything on the road at the time.
Some have claimed that the crackerbox was available with the 475 hp 12V-71 Detroit Diesel, but not from the factory for highway use. There was a special order for a number of these off-road rigs that used the 12V-71.
Here’s a few more crackerboxes in assorted roles. All these wonderful shots came from Dick Copello’s fabulous collection of truck photos, many he shot himself over the decades.
Here’s a haybox.
And another Bekins.
The crackerbox inspired similarly-boxy competitors from the other Big Three, as in this Ford W-series from 1966. This was considered to be a rather weak competitor in its field too.
And even Dodge jumped in, with its L series, from 1965. Given Dodge’s weak market position and the lack of any prior COE trucks, this was ambitious and a bit surprising. It didn’t help solve Dodge’s problems, and lasted until 1975 when Dodge exited the market.
Ironically, all of the independents’ COEs, like this Mack, all had a bit more style than these flat-planed boxy ones from the Big Three. Which may explain a whole lot why the Big Three all petered out in the HD market: image. Just like American cars started to lose their status to the imports, the Big Three’s big trucks also started to lose image and status compared to the independents.
This change really took off after the West Coast trucks like Kenworth and Peterbilt opened distribution in the East in the late ’60s. Their distinctive long-nose big-grille conventional trucks came to define the big American truck, and this image rubbed off onto their COE models too.
The DF Series crackerbox was replaced in 1969 by the Astro 95. It was conventional in all regards too, except for its styling, which it actually had. In fact, it was a leader and ahead of the curve, in predicting a turn away from such brutalist and utilitarian boxes. It was influential in that regard, and it helped keep GMC in the game for a while longer, until 1987, when GMC exited the HD market. A Chevrolet version, the Titan, was also built, but that ended earlier, in 1980.
Ford responded in 1977 with its CL9000, quite advanced in having its cab be separately suspended, as this one listing to one side makes quite clear. It was the solution that the Europeans have used for decades to make their COE trucks comfortable. But the market spoke, and Ford bailed in 1997, selling out to Freightliner.
Why did the once dominant GMC Truck division fade away after 1959? The DLR/DFR8000 was clearly a watershed, although it was inevitable anyway, as a consequence of GM’s management structure. Once GM became fat and happy in the mid 1950’s, it failed to appreciate that it was actually highly vulnerable, on all fronts. Instead, its fast-track executives were assigned very short terms at the various divisions like GMC, Opel, Frigidaire, etc., to essentially put in time, before their next more plum assignments at one of the car divisions and then a corporate job on the 14th floor. The guys doing the actual work at the non-car divisions and plants never got a proper voice or good leadership.
And here’s a smattering of those GM execs in 1959, basking in the reflected glory of their latest creation, which was destined to take the semi truck market by storm. How much do you want to bet that not a single one was capable of driving it?