After GMC’s brutalist “crackerbox” tractors, its successor, the GMC Astro was a relief for sore eyes. Arguably the best designed big COE tractor of its era, the vaunted GM design Studios got it right this time.
Chevy wanted in on the action too, and got a version dubbed the Titan. The only difference was a change to the grille texture and of course the badging. This one sports the smaller grille of the original series, which I rather prefer.
When the Astro and Titan arrived in 1969, this was a whole new ball game in terms of big truck styling, which had generally been sorely neglected since the 1940s or so. Sure, there were some very handsome trucks, but they were so because of their intrinsic proportions more than actual professional styling. The Astro and Titan, as mundane as they may look now in hindsight, brought a whole new level of design considerations to these COEs, such as massive front windows and a high driver’s position that made visibility unparalleled. The dashboard was also designed for best sight lines, and had a very modern feel to it.
Compared to the odd-ball COEs from the 50s, mostly cobbled up by jacking up other cabs and the crackerbox brutalism of the new ’60s COES, this heralded a new era, and everyone in the industry had to invest in new modern cabs to keep up appearances.
The high driver’s position, ergonomic steering wheel angle and visibility is apparent in this shot.
Unlike its predecessors, the Astro/Titan only came with diesel engines. The base engine 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.
It appears that the much larger grille arrived in 1977 with the availability of the Cummins KT450 and Caterpillar 3406. I was not a big fan of that big new grille.
There were also some advanced aerodynamic versions, but we’ll get into those when we do the Astro by itself.
During this era, it had been decided to let Chevrolet trucks share the full range of HD lines that had once been the exclusive domain of GMC. But that strategy didn’t pan out, as it required Chevy truck dealers to be able to support a much wider range of trucks, with expanded facilities, parts and expertise. So in 1980, Chevy truck reverted to just the medium range, and the Titan and Bison and Bruin conventionals were dropped.
The GMC Astro continued through 1987, but in 1986, GM had already decided to exit the HD truck business, having entered a joint venture with Volvo, in which Volvo took an 85% controlling stake. That lead to White (owned by Volvo) designs replacing the Astro.
Your statement about some older trucks being handsome because of inherent proportions is spot-on. When I worked at Peterbilt in the late seventies through early eighties, there were no stylists or industrial designers. The new product engineering manager had an architecture background and obsessed on proportion; surface detail was pretty much left to the design engineer dealing with materials, manufacturing methods – and design technology. We were still using French curves and radius templates for any shape that wasn’t a straight line. We hired a contract ID guy to develop some interior designs around 1980, and I believe in-house ID was brought in sometime later. As for the Astro, I always though it was a great design, and far better looking than the fussy Ford CL9000 that came along later, but most of my fellow Peterbilders looked down on those as “Detroit trucks”.
You should write a comprehensive article about your Peterbilt days!
About the CL9000. In the early eighties, I bought a book about heavy US trucks and was mesmerized by the CL9000 interior pictures. Stunning! And a cab with air suspension, who else offered that in the late seventies?
GM’s 1969 top model tractors are looking mighty fine. There must have been a few around here and in the surrounding countries, but the Mack F-series prevailed. And I’m sure I spotted a Kenworth K100 now and then during my childhood-on-highway trips.
dman I will echo Johannes, I would love to hear more about your days at Peterbilt during that era.
My dad bought a new Sierra in ’79, he brought home all the brochures for 5-year-old me. At that point the Astro still had the original small grille as standard, I think the big one was phased in over a couple years.
I always thought that the big rigs from the Big Three should’ve been aimed mainly to small-fleet/midsize business operators who may only have run a rig or two but many more pickups, vans and sedans. One contract with one dealership for the entire fleet.
Related reading
https://www.curbsideclassic.com/blog/cc-outtake/big-truck-outtake-gmc-astro-95-it-makes-me-want-to-go-boating/
The Titan 90 was talked about in a previous story on this website. As I mentioned at that time, much of the interior and the dashboard were designed by a woman named Martha Jayne Van Alstyne, who also worked on the interior of the ’68 Corvette. Hired in the 1950s, Van Alstyne was one of the female designers mentioned in the book, “Damsels in Design,” by Constance Smith which came out several years ago and which was mentioned on this site and on others. Van Alstyne spent most of years at GM working in the Frigidaire division working on kitchen appliances.
I drove one of these just once, a pick it up here and deliver it there job. It was an 8V-71 with a 10 speed RoadRanger. Unlike some rigs, this sleeper cab tractor drove beautifully and seeming without quirks, and I felt right at home behind the wheel almost immediately. That immediate feeling of familiarity and and satisfaction certainly wasn’t always the case. No one I know would have had the same reaction if you were assigned to jump into a B-series Mack Thermodyne Diesel with a Tri-plex or Quad-box transmission, for instance. The Astro/Titan trucks were very impressive in every way, in my opinion. It is unfortunate that their “dynasty” had such a short life. Nowadays, their is a lack of diversity in almost every kind of vehicle of this kind, both in trucks, farm equipment, construction equipment, etc., and many good brands have been lost but not forgotten.
Back in 1983 when I was 18 years old, a local community college offered a 10 week truck driving course for a Class 1 license which later became a CDL.
The course ran for 10 consecutive Saturdays and two separate classes were held simultaneously with each class having an instructor and three students.
One truck was a GMC Astro with a Detroit 6V71 with a 10 speed roadranger while the other was a Chevy Titan with a Detroit 8V71 with the 10 speed.
Each truck was paired up to a 48′ or 53′ trailer.
Both trucks had sleeper cabs with the rear bunks removed and seats installed in their place so that the instructor and three students could ride in the cab at the same time.
The instructor would sit in the front passenger seat and a second brake pedal was provided on the passenger side floor so that he had the ability to stop the truck from his seat if a situation required it.
We three students would take turns driving throughout each class day which usually lasted 6 or 7 hours.
We were assigned to the 6V71 powered Astro for the most part, but on a couple of occasions, the two classes would switch trucks and we would have the 8V71 Titan for that day’s class.
When the course was completed, the truck and instructor was provided to bring the truck to a specific location to meet an examiner for the students to take the road test for their license.
I passed the test and got my license but never did end up making use of that license for a truck driving job but kept it for over 30 years before downgrading back to a standard license.
I came close to getting a passenger endorsement 20 years ago wben I was considering getting a job as a commuter coach bus driver driving MCI 45 passenger coaches.
Dave, What community was this? It still sounds like a good idea.
No kidding, that sounds like a great opportunity for a solid paying job right out of school.
Those trucks must be the first of the modern era, some features remain in place on newer models from other manufacturers the vast dashboard of switches and dials for instance and the climbing wall entry system neither of which are driver friendly safety focused or ergonomic, I see they had roadranger gearboxes simply the best thing ever developed I love them, but since moving to city driving am beginning to appreciate automatics more
Like GOM I got to drive a Titan once. Same deal sort of, transporting it from seller to buyer both friends of mine but I was the only one with a license. My ride was a daycab 8V-71 with the 10 speed. That sucker did well you are really up there in one of those. I10 out of east LA. is in terrible shape, you can’t see it as well from a car. I was also looking well over the tops of most of the conventionals I passed on the way home. Another friend now owns it and I saw it yesterday.
The Astro/Titan was a decent truck, there were some problems. One that was a major mistake was having a single lift cylinder for tilting the cab. The cylinder was located on the passenger side of the cab. As the truck aged the aluminum cab would twist as you lifted it and it was a pain to get up and back down. Some of the really bad ones required a bit of persuasion with a pry bar. The day cabs usually were OK it was the sleeper cabs that suffered the worst. I never saw any other brand of class 8 cab over use a single cylinder for lifting the cab, Pete, Kenworth, IH, White, Freightliner all used twin cylinders.
The other odd thing was the throttle linkage. The throttle pedal not directly connected to the engine. The throttle operated a paddle that was mounted on the under side of the cab structure. The engine throttle linkage terminated under the cab at the paddle using a roller for the interface. The roller was about the side as the rollers used for garage door
tracks. When you stepped on the throttle the engine torque up against the motor mounts and it would lift the roller into cab paddle giving you more throttle. Then you let off and the torque drops off the engines sets back down and the throttle close some more. So you would get a herky jerky movement and the cab jacking up and down. Throttle by wire couldn’t come soon enough.
One of the reasons for GM to dump the the heavy duty trucks line was the lack of capacity. They were constrained to much by the plant and could not expand production. So rather than expand or build a new plant they sold it lock stock and barrel. Astro’s and General’s were killed off almost immediately, Brigadier’s did hang on for awhile.
GM did have a fair market share but their Detroit Diesel engines has soured a lot of customers and I would assume the profit margin probably dropped a bit when you had to put a Cummins or Cat engine in to compete.
Don’t forget the rear engine mounts.
Great design for a mount, sort of a “clamshell” that closed a rubber isolator over the actual metal mount “ear.”
The problem was in some builds the clutch housing couldn’t pass between the mounts. Necessitating removal of the mount from the chassis. That can be a BIG deal.
Other than the mount issue an Astro transmission removal could be about a 20 minute job.
Yes the mount was a clever design and I wonder why they didn’t use it on the Brig or the General? Some of the Brigs and its predecessor’s had horrible rear engine trans mounts. As any one familiar with GMC heavy trucks will tell you GM typically put the rear engine mounts on the transmission bell housing rather than the engine bellhousing. The frame mounted piece was under the trans mounted piece and the trans mounted piece overlapped the frame piece to the front and rear. This meant you had to jack it up quite a bit to clear the frame mount to pull the trans rearward for removal. Lastly if the truck had a 8V-71 the exhaust pipes ran directly above and right on top of the motor mount bolts so you had to pull the exhaust to get the bolts out. More than half of these the bolts were rusted into the motor mounts so bad you had to burn them out.
The Astro 95/Titan 90 were also one of the first heavy trucks to offer integral air conditioning. Most heavy trucks at the time used a hang-on system like the Kysor or Thermo-King with a roof mounted condenser box. Those systems were not too reliable and even when they did work were not very efficient. The Astro had a Harrison HVAC system in the dash, condenser behind the grille, and the good old Frigidaire A6 compressor. Even had a separate blower and controls for the sleeper. The system worked well and could even keep the large windshield defrosted
The Astro A6 was the first automotive application for a flat multi-groove V-belt (like everything has now) that I recall.
That poor A6 wired as a clutch slammer, driven via a no-slip big belt and heavy accessory drive. It could have to go from a peaceful slumber to BAM! full load and speed, right now! lol
I don’t recall an Astro with 6v-71.
You gents?
Not saying there weren’t some, but I sure can’t “pull one up.” lol
Never saw one with the 6V-71, but did see a few with 6-71 in-lines.
Agree, I never saw a 6V-71 in any truck, kind of a rare one.
The other odd one was an Astro with a V8 Cummins, I think it was a 903, maybe a Triple Nickel? It stood out to me as it had special frame rails by the engine because the engine was too wide for standard rails. Sure wish we would have had digital camera’s back in the day. The reason this stood out was how I had to repair it. The alternator was on the fritz and needed to be fixed or replaced. The alternator was belt driven off the front of the engine. The cab wouldn’t jack up. Pump was leaking. Then the driver pointed out that we would need to unload the storage compartments. He pops open the drivers side storage compartment and the compartment was stuffed full of these cardboard boxes, fairly narrow box and very short in height and fairly long. What was this? Cutting edges for ag plow moldboards. There must have been a thousand pounds of these things in there. Sorry, not doing that, I called over the top of the engine to get that alternator out, repaired it and popped it back in.
I saw GMC Steel Tilt Cabs with 6V-71’s in them. The cab was raised up to clear the engine and had filler pieces in the fenders. The trucks were tandems set up as car haulers. Pacific Motor Trucking had many running on the west coast.
The source of that was obviously incorrect. Text amended.
Last one for the day. A leasing company had purchased about a dozen or so Astro’s from us. Day cab tandems, 855 Cummins and ten speed road rangers. The Owners had pointed out that they had spec’d that the rear engine mounts must be mounted on the engine bellhousing, transmission mounted rear engine mounts were not acceptable. I remember when the buyer came down to inspect these trucks that it was the first thing they checked. They hated the current Astro’s and other GMC’s they had with GMC’s normal configuration. Well, that meant this ten speed was hanging off the back of the engine all on its own, no rear trans mounts. About six months later we got our first one of those in on the hook. Bellhousing bolts had failed and the trans is half falling out of the truck.
This was another odd thing if you worked on lots of heavy trucks. Most manufacturers used 7/16″ bolts to attach the trans bellhousing to the engine bell housing. GM used 3/8″ bolts. Now 3/8″ bolts are adequate for the job but give me the choice and I’ll take the 7/16″ bolt.
GMC’s fix for the poor Astro’s? Install a rear trans crossmember and used 3/8″ lock bolts to secure the trans to the engine. A 3/8″ lock bolt uses a “fat” thread for an interference fit which meant no spinning the bolt in with your fingers, torqueing the bolt is kind of guess work because of the interference thread and the bolt is threading into an aluminum housing, stripped holes anyone?
Well, isn’t that special! What other engineering details of the trucks did they believe they could specify without consequence? The distance down from the piston crown to the top ring land? The colour of the brake linings? The minimum and maximum radius of bends in the fuel line? Wait, wait, don’t tell me—the acceptable number of teeth on the drive axle’s ring and pinion. Seriously, WTF was with this preemptive second-guess of the factory engineering? I’m not about to claim GM always get everything right, but this no-trans-mounted-rear-engine-mounts specification seems bizarre, arbitrary, poorly-informed, and—as you describe—um, consequential.
This was a very common bitch in the industry about GMC rear engine mounts.
You did run into similar mount configurations on other makes of trucks It was somewhat more common though for the engine to have mounts front and rear with a third on the rear of the transmission.
On the GMC’s the trans mounts interfered with moving the trans backwards plus you had to deal with supporting the rear of the engine.
There were trucks that were a pleasure to do a clutch job on and there were others that were a real pain. when I started in the industry truck lifts were very rare. So you were crawling around under the truck to get the trans out to get the clutch out. Cabovers were generally pretty nice to do a clutch or transmission job on unless it was a truck something like a garbage truck where you had a body on it. If you had to get the transmission out from under the truck that could be a whole new problem on some trucks.
Fine, then the legitimate option was to buy trucks from companies who built them the way they thought they wanted. Equipment specs are one thing, but pretending build specs were a-la-carte like this evidently made the problem worse for everyone.
Hundreds, easily hundreds, of stripped Jimmy housing holes.
I believe it was an OEM IH piece, a “stepped” stud that was 3/8″ x 7/16″, a favorite go-to.
…in the large bag of tricks necessary for housing repair.
The Detroit’s were the worst to fix, not a lot of material around the hole for using an insert, heli-coil was about your only choice.
Wonder why that wanted the trucks set up that way, faster clutch replacement?
Lots of trucks were built each way.
Clutch change-out was a pain with the GM housing-side-mount configuration.
However, I’m not ready to blame the mount relocation for the pull-out problem.
GM seemed to have the epidemic of housing strip-out, maybe the altered specs hoped to alleviate that too?
Meanwhile I had another flashback… who else “rolled” the transmission to get brand new fresh “meat” to drill and tap into? After those pulled out a time or two it could be rolled the other way for another new fresh start. lol
Never heard of anyone rolling the trans for fresh meat. I could see a fleet doing it but most repair shops would be reluctant to do it.
Fixing a Cummins or Cat wasn’t that bad because a new bellhousing wasn’t too expensive and not a lot of additional labor. The Detroit’s were the real headache because you had to replace the gear train housing and could be a really labor intensive job depending on how many accessories were driven off the rear of the engine.
Easier clutch and transmission repairs. Time is money to a fleet. You would be amazed at what a manufacturer will do to get a customers order. Especially a large customer. Then throw in the fleet service personnel and operators with their pet peeves and they can filter thru to the top.
True, been working for large fleets for over 30 years now!
Probably not a concern to anyone because no doubt the customer and GM were aware of the fact that many large transmissions were successfully “hanged” without any mount or support whatsoever
Sure, granted, but did it not occur to this particular fleet that specifying no transmission-placed rear engine mounts so as to make clutch jobs easier might wind up making other, bigger, costlier, more time-consuming problems? Just because they’re allowed to specify whatever they think they want doesn’t necessarily mean it’s a smart or cost-effective decision, and I surely wouldn’t think it out of line if GM said “This is what you wanted, so this is on you” when the fleet’s arbitrary little specification came back to bite ’em
I saw many trucks that should not have been built. Some that should have been shut down by the factory engineers but others were the results of mistakes and sometimes shall I say “misleading” information. We had about two dozen single axle plow trucks with air ride rear suspension. It was a test to see how the suspension would stand up as we were having lots of trouble with broken springs. After 3-4 years in service we were having some issues with broken parts and corrosion. When we contacted the suspension manufacturer they told us that the suspension was not rated for our application. The build orders had these trucks listed as a pick up and delivery truck, not a on/off road vocational application.
It wasn’t until the late 90’s that I saw a more concerted effort to spec trucks and then check there performance on computer programs to assure the truck could perform its job.
Trucks (…cars, carburetors, etc…) that shouldn’t’ve been built strikes me as a terrific topic for at least one CC post!