I don’t know anything about this photo except that it features three very different GMC trucks. Let’s take a closer look at each of them, starting with the likely most familiar one on the left, the handsome GMC Astro.
We’ve never done a proper post on the Astro 95, which arrived in 1969 and was undoubtedly the best-styled and most modern cab-over (COE) semi truck at the time. The GM design center decided to get serious after their very crude and brutalist “crackerbox” DR/DF COE that preceded it. But we have written up its Chevy-badged twin, the Titan.
The base engine for these was the Detroit Diesel 6-71N, with the Detroit Diesel 8V-71 and Cummins N-Series diesels as options. In 1972, the Detroit Diesel 12V-71 became available as an option; though rarely ordered, the V12 engine would remain available through 1978.
Although Detroit Diesel had developed a gas-turbine version of the GMC Astro in the early 1970s, fuel-economy concerns would keep it out of production. In 1977, the Cummins KT450 and Caterpillar 3406 became options; the larger engines required the addition of a larger radiator. In 1979, the 6-71 was replaced by the 6V-92, making all available Detroit Diesel engines V-engines; the 6-71 was discontinued after 1980.
Although the Chevy Titan was discontinued after 1980, the Astro lived on until 1987, after Volvo AB bought a majority of the GMC heavy duty truck line.
The middle truck is a GMC heavy duty conventional truck (J Series) that was introduced in 1966. The V badge on its front side (and lack of a diesel exhaust stack) indicates a GMC gas engine V6, or possibly the new 637 CID V8, which was a V8 development of the V6, including its 60 degree cylinder bank angle.
Somewhat curiously, this cab was built with both a single pane front windshield as well as a split one. I’ve never heard of a good explanation of why; my one stab at it would be that the really big HD versions had greater torsional flexing from the torque of their engines. Anyone else know?
There was also a long-nose version to accommodate the biggest diesel engines, and it came in a Chevy version too, like this one, but the Chevy was a pretty uncommon sight. This one has the split windshield.
The last truck is a bit of an odd-looking beast but was a genuine pioneer. It arrived in 1957 featuring full air suspension, thanks to GMC’s extensive experience with that in its 4104 coach and transit buses. It used the older GMC-exclusive cab but managed to add aspects of the GMC pickup-medium duty trucks on the front of it.
A steel-spring version soon came along too, and that the featured truck in the picture at the top is likely one of those. But it does have a diesel engine stack, which would connect to the standard DD 4-71 engine, possibly a turbocharged 4-71T making 171 hp, or a 6-71 in several versions.
I always liked that DAC chose the “57 GMC Pickup”
as the personal vehicle of the “redneck” whose mother made him what he is
Fantastic artworks .
-Nate
The only explanation I have ever heard on the J series windshields was the 9500/90 series trucks used the split windshield to reduce replacement costs. The idea being those models were more often used for over-the-road work and would suffer windshield damage more often. With a 2 piece windshield only the broken side would need to be replaced. The cabs on the J series were welded steel and were quite sturdy, at least until they rusted out…..
I have copy of the 1967 Chevrolet brochure for the series 70 and 80 lines. These were Chevy’s version of the J series. In the “Cab features” section it says that Series 70 got the one piece windshield and Series 80 got the two piece, but no explantion as to why.
The 2 summers I spent working for an excavating company had me driving a dump truck. Most were tri-axle J series GMCs with 6-71 Detroits and a 15 yd. dump box. A few tri-axles were Internationals
In construction, seniority ruled. The larger trucks paid more, so as a junior guy I never had enough seniority to draw a GMC or International. I was put on a dual axle Ford F series gas with a 10 yd dump box.
On a job, the smaller Fords were normally directed to dump in areas closest to structures. The shorter dump boxes would also clear overhead wires the 15 yarders couldn’t.
A consequence of this seniority system was the least experienced drivers were making the riskiest dumps. Go figure.
One on the left looks like the one on the opening scene chase in Beverly Hills cop, that oe was a single axle tractor though.
Mike:
My comment about “as few axle as possible” on a truck in America seems not to have been posted, as well as mentioning how semis in Canada had 3 axles on back of the trailer.
Nice, I love to drive an old truck, and maybe own one one day in my dreams.
I would never have known that the Astro 95 COE(cabover engine) was a product of
the late 1960s.
COES(or flatnoses as I called them) were a product of smart packaging and space utilization that aged very well appearance-wise, compared to conventionals//long noses.
Supposedly Larry Shinoda worked on the Astro 95’s styling. The wrap-around dash was very innovative at the time as well.
I worked as a carpenter for a company that provided residential treatment for teenage offenders. They own many motel-type properties, as well as old homes that were run as group homes. They were always doing renovations, changes, upgrades. They owned a J Series dump truck that was bought used from the Navy Base in Norfolk. Very low miles for this reason. It was used to dispose of construction debris and large items that couldn’t go in the usual trash dumpsters, taking the waste to the garbage to energy plant in Portsmouth. Only got to drive it a couple times, as I made too much money to do that job. It was a good workhorse, and I’ll bet it’s still in use 30 years later.
My friend Dave sent me a shot from a local Home Depot parking lot. This beauty is like the Ford cousin of the J-Series GMC in the center at top. It’s a double cab and the license plate says 1968. Can anyone tell me where this falls in the F-Series?
Given the wheels, it looks to be on the lighter end of the N-Series spectrum, like an N500 or N600.
I’ve never seen one of these with a double cab; very unusual.
Thanks Paul! I knew you would come through.
After driving the crummy for a logging company in the ’80s, I’ve always had a thing for double-cabs. Especially Ford and IH.
Interesting. Today I learned the J trucks were, well, J trucks. I always liked the looks of them; thought they looked very modern, sleek even, in the 70s and through the 80s. I didn’t realize they came out in 1966, and must have seemed Buck Rogers modern.
Their overall silhouette and oh-so-cool sounding Detroit Diesel engines drew admiration from me as a kid/teen/young adult. I liked that solid drumming knock from a 6-71 at idle and then transitioning from idle to part throttle. Music.
Always liked those round-ish Mack trucks too. I later found out they were much older and called the B-series.
I worked on many Astro’s and J series trucks and tractors.
The J series morphed into the Brigadier and the General took over for the long nose J series. I believe the Generals were available in a short hood and a long hood. The General was a very nice truck with an aluminum cab.
The Astro was a decent truck, its one short coming was the cab tilt cylinder set up. It used only a single cylinder on the right frame rail to push the cab up & over. The cab structure would loose some of its rigidity as it aged. When you jacked the cab up the rear of the cab it tended to shift to the right causing things to get out of line when you brought the cab back down. You had to use a large pry bar to kind of push things back in place.
The other fun part was driving an Astro tractor. The throttle linkage was unusual. The throttle pedal operated “paddle” that was mounted to the underside cab structure. The engines would have linkage with a roller on it that lined up with the paddle when the cab was down. If you stabbed the throttle to hard at first the engine torque would cause the engine to lean to the right, raising the throttle roller into to the paddle causing the throttle to open further. The usual reaction from the driver was to let off the throttle some, but the drop in engine torque would cause the engine to drop back to the left pulling the throttle roller away from the paddle. Lots of herky jerky driving until you figured out right application of throttle. Of course worn or loose engine mounts made it even worse.
Its a pity that GM let the big stuff go. Volvo combined GMC with White for a bit. But the hand writing was on the wall, Volvo was just buying up the competition and shutting them down. Volvo quickly killed the Astro and General, the Brigadier lived on a for a few years and then it was killed too. The White/GMC were just a new badge on a White truck and eventually that badge changed to a Volvo badge.