(first posted 10/15/2016) There are highs and there are lows…that old adage certainly sums up GM’s long history of intercity coach manufacturing. From the highs of the 1940’s, to its peak in the 50’s, to the parity of the 60’s and then the decline in the 70’s – let’s take a look at the last intercity models to come down the Truck and Coach assembly line in Pontiac Michigan – the GM “Buffalo” series…
For our non-bus fan readers, you may be curious as to how the model acquired this nick-name. Think of a buffalo, with its shoulders higher than its head and neck – the 4107/4903 with its higher raised floor and lower front driver’s area could be considered somewhat similar looking.
Next, a little history. The GM PD 4104 “Highway Traveler”, produced from 1953 –1960, was a major leap in technology and innovation – the first intercity bus with full alloy monocoque construction, air suspension, and large slanted picture windows – it was leagues ahead of any of its competitors, established the standard for the modern 35′ coach, and was a huge success for the company.
The PD 4106 followed, built from 1961 to 1965. It was essentially an updated 4104, with some stylistic changes, larger windows, and powered by the recently introduced 8V-71 diesel, which allowed a new efficient combined heating and cooling system, with the compressor driven off the engine rather than a smaller auxiliary motor.
MCI 7
Eagle Model 05
So what to do next? Well, transit operators were looking for larger coaches – ones with more under floor storage space and in lengths greater than 35 ft. At this same time, Greyhound was transitioning to an all MCI fleet, and Trailways was committed to its Eagle brand coaches. GM looked at the remainder of the market and decided that to be competitive, it needed to field a bus in both 35 and 40 ft lengths, but with a raised floor to offer competitive underfloor storage.
While the PD 4501 Scenicruiser had a series of mechanical and structural issues that caused Greyhound headaches, from a marketing and publicity perspective, these and GM’s other coaches were hugely successful. My guess is GM thought it could leverage some of this Scenicruiser “brand value” and that led engineers and stylists in the direction of a bi-level, stepped design.
Of course it was also just expedient, as the whole front end was essentially identical to the 4106, and the rear just elevated. In 1966, GM introduced the PD 4107; P = Parlor (the name used since the 1930’s to designate a highway coach) D = Diesel, 41 = Typical Passenger Load (depending on whether lavatory installed), 07 = Model No. The 4107 was a 35 ft bus, somewhat similar in looks to the PD 4501 Scenicruiser, but without the front low seating area and restroom. Rather than having 5 rows of seats on a lower level behind the driver, the 4017 had three stepped rows, each having 4 seats, going from the driver’s area to the upper floor, similar to stadium seating.
In 1968, the PD 4903 debuted joining the 4107, with an extra five feet spliced into the bodywork between the front and rear wheels – making a 40 ft coach. The 4903 also introduced a 24 volt electrical system, the first on any bus.
Both versions used GM’s 8V-71 engine, arranged in a “V“ drive configuration. Transmission was a 4 spd Spicer unit. Overall, these buses enjoyed a good reputation; they exhibited GM’s excellent build quality at the time and the extended wheelbase 40 ft models rode very smoothly.
My research turned up only two criticisms; they were notoriously rough shifters – the non-synchronized Spicer box required double clutching, and even then gears tended to grind. And while the extended wheelbase gave a smooth ride, it made for a low bus that would often bottom-out or scrape its undercarriage on uneven roads and while leaning in turns.
Greyhound purchased 162 4107’s in 1966, and a further 200 in 1967 – but with MCI production capacity now able to meet its demands, these would be the last GM coaches the company would procure – thus ending a storied 30 year partnership. The bus in the picture above, No. 5028, was the last one delivered to Greyhound.
Minor updates, a synchronized Spicer transmission and improved driver’s area, came in 1970 with the PD 4108 (35 ft) and 4905 (40 ft). Even with the new transmission, driver’s continued to complain about shift quality.
A tag axle could be added to the third luggage bay of the 4905 for those states with lower axle loading laws. It should be noted that the 4905 was the only American 40′ coach that didn’t require a third axle in many/most states; the other 40 footers all had two axles in the rear. GM’s design and construction made for the lightest coach in the industry.
Throughout the 1970’s, sales gradually dwindled. In 1972, GM changed the model designations from PD 4108 and 4905 to P8M 4108A and 4905A, respectively – equivalent to its transit coach naming convention. Then finally in 1979, the 4905 was renamed H8H 649. An Allison automatic transmission was available on these last two years of production. The final Buffalo produced, No. 233 pictured above, was delivered to California-based Eastshore Lines in 1980.
So, what’s the overall verdict? My take is the Buffalo clearly wasn’t a bad bus – it was just not the definitive segment leader its predecessors were. Its contemporaries, the MCI 7/8, and Eagle 05/08, were equal, if not better than the Buffalo. Also sealing its fate was the sharing of some manufacturing techniques and components with the New Look transit coach. The New Look ceased production (in the US) in 1976, supplanted by the RTS II which used a new modular construction process. With its sales decreasing yearly and no longer able to spread production costs across two platforms, post 1976, the Buffalo was living on borrowed time.
Total Buffalo production over 14 years was 4530 coaches – quite a few can still be seen on the road today as motor home conversions.
So that “WRONG BUS” sign in the destination window in the top photo proved prophetic…..
Great story. Seattle Metro had two 4107’s in their suburban fleet (most were 4104’s) and I do recall them being crazy shifters. In the early 70’s, transit systems were hiring a lot of women and unfortunately some of the new hires had a difficult time shifting PD’s. Even a few men had a tough time learning to double-clutch the Spicer gears. It wasn’t long before they were phased out, replaced by transit style buses. When I moved on to LA’s RTD, they were in the process of changing the suburban buses to automatics. The story was similar to Seattle’s. The ladies couldn’t handle the manual shifting and clutches were allegedly being burned out. I’m sure a few male new hires fell into that crowd too.
Why were they even installing stick shifts in buses in the 60″s? In 1962 I went with my dad to pick up a Mammon-Harrington 40 passenger school bus in Indianapolis, Indiana and he drove it to Portland, OR. It was a roughly the same size and a pusher like these intercity buses and had a 534 Ford and Allison automatic transmission. The trip had no problems and the bus was run mainly at it’s top governed speed of 65 MPH. So why the manual transmissions in the intercity buses?
Tradition, economy, durability, etc.. The Spicer four speed had been used for buses for decades, and operators don’t like taking risks. Also, I’m not aware of the Allison automatic being ever teamed up with the DD engines. Maybe there was a reason?
But yes, shifting all of these manual buses was a chore, and a skill some got quite good at; others not. Even city buses had manuals going into the 50s, as some operators were slow to adopt the torque converter drive available as of about 1948 or so.
2 stroke Detroit/Allison powertrains were very common in trucks back in the day, and a lot of the later MCI coaches used those engines and transmissions as well. I used to see Detroit/Allison powered Crown school buses and Gillig Phantom transits as well. Technically the V and Super V became Allison products, and the later V730 V-drive was an Allison design. Remember that from the early 70’s to 1986 Detroit and Allison were combined as the DDA Divison of GM.
The operating characteristics of the 2 stroke cycle Detroits were well suited to torque-converter automatic transmission in many applications, though for highway service the earlier Allisons were not as efficient as manual transmissions.
Well, I’m not a mechanic in that sense. I was simply one of the bus operators that drove various stick-shift buses. The first time that I drove a 4104, I hung up the gears when I was down-shifting. Thankfully, my instructor was a former mechanic and while I and the passengers sat in the bus, he slid underneath it and after a bit, I saw the stick moving around… We made it through the rest of the day.
Snake bitten!!
I was considered qualified but downshifting was stuck in my mind. I caught a tripper and after I’d dropped off my last passenger and was pulling in, the dreaded moment came. But presto, I pulled it off! After that, I got cocky. Put it in front of me, I could handle it. Speed shift, no clutch, you name it!! I reasoned that I had a bad bus in the beginning.
“Loco Mikado”… I like the name although few here would figure it. One must have an understanding to the 4 ft, 8 1/2” degree!
Early automatics tended to be much more expensive to buy, and less fuel efficient to operate. Driving various ’50s – ’80s charter coaches, I found I could normally give my passengers smoother shifts double-clutching the manual transmissions than the automatics of the day. However, shifting could be pretty ugly with an inexperienced driver, or one who just didn’t care. By the late ’80s, the automatics were much improved, and manual transmissions faded away.
Hi, Larry,
I worked for Vern Trigg down in Portland & was the second female driver he hired. I had to learn to double clutch & at times thought I had a crow bar under my left knee cap.
A few years later, I worked for Raz, but he no longer ran any Jimmies. In 2008, I went to work for Bluegrass Tours in Lexington, KY, & drove a 4108 on its last two runs. I was the only woman who could drive it. Before I left KY to come back to OR, Wah Jones, owner of BGT told me I drove better than any of the men who had worked for him.
I retired in 2018. I loved the life & my job (the passengers not so much) & I miss driving the “big girls”, but I really love retirement.
Sincerely, “Stagecoach Annie” Dutson
I remember that. Great Post!!
There’s a youtube video of someone shifting a Buffalo bus, with a “If you can’t find em, grind em. ” I wonder why they didn’t use a synchronizer in those trannys , or go with automatics from the beginning ? It’s interesting that they appear to use passenger and rear windows from the “Fish Bowl” city transit buses, rather than from a 4106. The only thing I don’t like about the original 4104 is the awkward looking rear passenger window, emergency door set up. They could have painted the pillars back there black to make it look more integrated. That’s why I like the 4106s look better. Interesting CC, thanks !!
I remember riding on these for field trips during my high school years. They were popular with charter operators. One trip was out to Ocean City, and since most of us smoked, and I was tired of others bumming cigarettes from me, I bought some of those little slim gag explosives one could stick into a cigarette. I put the loaded ciggie into my pack and waited for the first one to bum one from me. Some time later, as we were rolling along, I absentmindedly pulled out one to smoke (yes, we could smoke on these buses), and as I took my third or fourth drag…BANG!, the thing exploded in my face. Talk about feeling dumb.
That’s my not-so-good Buffalo memory.
You were hoist by your own petard!
At the risk of sounding like an old guy pining for the old days.
I do miss when buses looked like this, with the aluminium sides and cool sounding and looking company names and logo’s, not to mention the sound of those GM diesels.
Now its just flat glass and usually white sides sometimes slathered with advertising you don’t want to read, not to mention mirrors that bow out from the top of the roof hanging down looking like some weird insect.
There I got it out of the way, feel better now.
The bus w/the Michaud name was owned by a company that was headquartered here in the Witch City (Salem, MA) for many years until the 1990s. One of the family members now owns the Witch Museum, a popular tourist trap, erm, attraction, that was once a private car museum before it burnt down in 1971.
As always, great pictures and good info here .
-Nate
With Spicer truck transmissions never use the clutch just float from one gear to another Eaton recommends using the clutch but Spicers shift easier and quieter without.
I’m sure Ive seen some buses that design in Aussie maybe not they might have been local clones nice looking bus though.
Vehicle naming and thus public image are important- imagine the bus named the GM Dowager or GM Quasimodo. 🙂
I like the Saskatchewan “Luxury Liner” the most. That color combination looks really good and it has perfect dimensions (overall length / wheelbase).
Carry on, keep them coming.
In GMC Truck and Coach sales brochure’s, the PD-4107 was shown as “Luxury Liner”, in the same font as that STC example…so they borrowed it from GM.
The new 40 foot version, the PD-4903, when it came out, was shown as “Super Luxury Liner”…
Of course GM T&C had the benefit of its parent’s art and design studio, with world class automotive and industrial designer’s….such as head, Harley Earl and Bill Mitchell. And it clearly showed, as the GM coaches were not only aesthetically pleasing, but they made the competition look awkward in comparison…
Interesting to see the tag rear axle…..was any thought given to making this steerable, now a very common feature on a full size coach in Europe?
I don’t know; I wasn’t in GM Coach’s engineering section back then. 🙂
Seriously, I doubt it, as these highway coaches rarely navigated narrow European-type city streets. They spent almost all of their lives on the highways. No need under those conditions.
The tag axle could not steer, but like a modern Prevost, they could be lifted with a switch on the driver’s panel…as a matter of fact, they could be retracted fully.
There’s an urban legend about a driver of one of these, when they first came out…
The New Jersey Turnpike charged commercial vehicle tolls by the axle count at that time. Companies that regularly operated on it, had charge accounts. When a driver approached the toll booth, he gave the ‘IBM’ card to the collector to stamp with the entry, and when he exited, he surrendered the card to that collector.
The story goes, the driver gave a two axle card to the collector. The collector looked back at the bus, and said, you gave me the wrong card…I need a three axle card. The driver flipped the retract switch, and then told the collector, that he was wrong…to look again. The collector’s jaw dropped and he shook his head sheepishly appologizing and then accepted the two axle card.
As soon as he got out of sight, the driver dropped the wheels down. And then did it again when exiting…:)
Hi i got a p8m4108a 1974 with the spcicer 4 speed 7145 vk it seem like there 2 type of transmission one with oil pump inside the belhousing and the other one without…. Do you know what the model of the one with the oil pump???
I really enjoy the article.
Amazing how much easier 4106s were to shift than Buffalos. MCI MC7 was the easiest shifting bus I ever drove. First Greyhound automatics had garbage truck transmissions. Shifted with a bang! Hurt the passenger’s necks if you weren’t careful. Eventually the shifting smoothed out.
Agreed! When I drove for Denver Boulder Bus Co. in 1973, we had a mix of 4106’s, 4107’s, a single MC-5. and a couple of MC-7’s. The MC-7’s had the early Allison automatic’s, the rest were 4 speeds.
I am not a mechanic, but I got the impression that the flywheel in the ’06 was heavier, or it seemed like it was…when you were shifting, you seemed to have more latitude to find the next gear. With the ’07, you had to be ‘spot on’, or you ‘lost it’.
The MC-5 sort of fit in between the two, IMHO. By far, the easiest bus I ever shifted, was the Eagle’s when I worked for Continental Trailways…they were almost like shifting a VW Beetle…:)
Thank you for your time and research.
I own number 32 of the P8M 4905A series.
I love it. It Is a real gem with its lines. The square mci and of course Eagle buses are fantastic but…….Buffalo has panache.
I have turned it into an RV to travel the east and southern coast line. My only issue is turning radius, none! Lol.
Thanks so much again for your research and time putting history to the masses.
Troy. Currently in south Alabama .
Hi Tony. this is Raul and I own a 4905 that run fantastic. I converted to RV and travel across country. in twenty years of going on road ,just two times I have a motor problem, and one was cost by a bed mechanic. any way is a pleasure to know you. gmcbufalo@hotmail.com
Yep, likewise.
They are fun for sure.
Mine is ready for a new owner though.
How’s about that new paint job
How’s about that new paint job.
Battleship grey. New new new.
Hot water upped to 40 gallon for the garden tub.
Electric panel updated to a slimline 50 amp.
We have “Celeste”, a 1978 P8M 4108. Fabulous for taking trips, but we need to put a turbo on her – power is a bit lacking going up hills.
turbo in not an option, I own a , 4107, the block can’t handle the pressure, beside on this engine you might gain 5 mph climbing, but, you will burn more diesel , you will have more trouble starting up,
I was advised by a very wise ex- greyhound mechanic and owner of a 4107
Lots of people asking “why no automatic” or why so few were automatic-equipped. AFAIK the answer is this. GM buses used a unique “V-drive” configuration with a transverse mounted engine. The transmission angled off at a 45-or-so degree angle to connect to the rear axle. This maximized passenger space but crimps your transmission choices. AFAIK the only automatic that will fit/work is the V730 Allison 3-speed automatic. Honestly, 3 automatic gears — or for that matter 4 manual gears — seems reeeeally marginal given that a GM 4905 is as big as a Silver Eagle, even if the GM is a fair bit lighter. But they sure are pretty, even if they evoke memories of the movie “Midnight Cowboy.”
Turbo charging is fine on the 8v71. I was a mechanic for Greyhound, 1974-76. Also worked for GM Truck & Coach division from 1978-1986. Turbocharged 8v71 were available, never could figure out why so few were used in buses. We had a MC7 fitted with a 350 horsepower 8v71 and a five speed Allison, that coach could move. The drive train was a testbed application to replace the 12v71 used in the MC6 coach. The GM coach was always a nicer riding coach than the MCI were. Another GM advantage was the use of a wet clutch with the manual gear transmissions. Seldom had a clutch problem with the GM coach. The MCI coaches were a bear to fix a clutch problem, always trying to get one more run out of the old girl before pulling the drive train out for repair. Automatic transmissions were a very expensive option and it seemed the bean counters couldn’t see the improved performance, less downtime and easier to drive coach as the benefit it would be. It seemed that the MCI was a lot tougher coach, loved the MC7. Hated the MC5, the dropbox arrangement for driving the differential and the driveshaft itself was always shaking itself apart.
Thank you for this wealth of information I am a recent owner of a 4106 and unfortunately the drive shaft apparently has come loose with the previous owner and completely cracked the transmission bell housing off from the engine needless to say I now need a 4-speed transmission for my PD4106.
We have just acquired a PD 4107 and looking for parts. Anyone know of parts anywhere? If you know of any please respond. Thanks.
I own a pd4107 makes me sick but I mite have to sell 9185047447
An experienced bus driver I once knew told me the Buffalo busses were IMPOSSIBLE to get around corners because of the long wheelbase and no tag axle. Never driven a bus myself, but it makes sense.
The long wheelbases gave a better more stable ride, as well as more usable underfloor space.
As for cornering, their front wheels could turn very sharply, to compensate. A driver does have to be careful making sharp corners, but on the other hand, there is a much shorter rear overhang to worry about such as when pulling away from curbs or other adjacent obstacles…
As long as the sharp corner were larger than say….a baseball field.
I’ll be the first to admit… the 4905 will corner Better in reverse.
Well Dave, I run a 4905a as a conversion RV. (#921) Corners not a problem at all. Even with a 24 foot trailer behind. Just use whatever room you have, and use your eyes, common sense, take your time, and caution.
I loved driving these. In Canada we called them the GM Hump. I drove for Voyageur Colonial Bus Lines. Most GM coaches were really fast shifters because the rpm’s would drop very quickly during shifting. So you had to double clutch and shift into the next gear before the rpm dropped to the bottom and bounced slightly up to idle speed. If it bounced then you “missed” the gear. I watched a seasoned pro shift one and he wasn’t sweating profusely like I was. He would press the clutch in about an inch, pull it out of first, release the clutch, push the clutch all the way in, THEN release the throttle. This gives you time as the rpm’s start to drop. You’re actually waiting for the drop, instead of racing to beat it. As the RPM hits the bottom, shift into the next gear. I copied this and got very smooth at shifting and was complimented often. My instructor referred to me as “the GM man” !!
35 years behind the wheel and more miles than I can count ! My first bus was a GM Humper (Yup. Canadian):) 35ft. My biggest beef with the humper was the AC rarely if ever worked! July and August was like Hades on earth. Turn on the ac passengers would say. How can I when we don’t have any? I used to open the front roof vent facing forward and the rear vent facing to the rear. It wasn’t too bad as long as you stayed above 60mph 🙂 All to act as a gigantic air scoop. Last ditch effort only.
Somebody once told me that the early Scenicruiser models (1950’s?) came with 2 engines. They’d sync up two 4 cylinder diesel motors . How in the heck did they do that? It only took me a month or so to get the hang of a 4 spd Spicer. I’d still like to take a scenicruiser for a spin just to say I’ve driven one though. 🙂 And then God smiled and blessed us all with Prevost hahahaha. The GM 60 series was the best engine to hit the road at least in my career anyway! The Series 55 was an unmitigated disaster.
Thanks for the memories folks.
The ScenicCruiser originally had two 4-71 engines. One of the difficulties with two engines is getting them synchronized. What happens is one pulls harder while the other loafs and you have an engine that needs replacement and then it starts all over again. I worked for the Dog back in the mid-70’s and two guys in the engine shop had been there when the Scenics first arrived on the job. That bus kept them very busy until the 8v-71 arrived. We still had 3-4 of the Scenics left when I was there. These were freighters and they had millions of miles on them. I think they were in the 6-8 million mile range if I recall correctly. The new MC8’s were delivered thru our shop. I did check-ins for a bit. I had kept an eye on one of the new ones as it came thru our shop on hotshot runs. I think it had been in-service about 4 months and it had racked up about 90,000 miles already. The new coaches were ran hard. Seattle to New York and Seattle to Chicago were two of the hotshots that I would see on my shift. When one showed up it was pulled in directly past all other buses waiting for service. Wash, Fuel, sweep, service the toilet, under chassis inspection, fluid level checks, interior swept and out the door, probably on its way in less than 15 minutes.
I do remember the GMC coaches, I thought they rode nicer than the MCI coaches but they weren’t as tough. We had more structural repairs on them than the MCI’s. Some GMC’s were had crappy A/C systems. We serviced other buses besides our own, Jefferson Lines, Zephyr Lines, Jack Rabbit and an occasional Trailways. Zephyr had a late model 4905 with the tag axle setup. This bus used twin 6 cyl axial compressors for the A/C system. Only one I ever saw. The A/C guy hated that thing, it was always braking down. Another weird one was another 4905 that had a unique V-Drive transmission. The transmission control on the side dash was a simple two pole toggle switch. Neutral in the center position, up for forward and down for reverse. The other weird thing I never figured out was what was used for parking brakes on the MCI’s. They did not have spring brake canisters. The most dangerous thing was if a bus ran out of air before the brakes were set you couldn’t set the brakes. These weren’t like a trucks that would automatically set when the air dropped below 30-35 psi. The was an MC5 parked with a pallet of wheels behind it and the pallet of wheels was in front of a block wall. This sad old MC5 was sitting down on all 4 corners all air leaked out. A bad habit a lot of guys had was popping into a bus to move it and not checking before starting. If you don’t have air pressure once you start the engine you can’t shut it off unless you stall the engine or pull the emergency stop. The problem is you can’t stall the engine if you don’t have air for the brakes and 1/2 of the emergency stop mechanisms are corroded and stuck. SO this guy like many others has flipped the switches on and hit the starter button before he is even in the seat. The bus was left in gear it lurches and proceeds to shove the pallet of wheels thru the wing wall before the guy can yank it out of gear. I left Greyhound after 3 years, I could see the writing on the wall. Every year after the holiday rush there were layoffs. The third winter they got me. Seemed like if the pay went up 10% they layed off 10%. Mechanics didn’t get paid all that well, drivers got the money. Oddly enough my Greyhound experience would land me a job with the GMC Truck and Coach division of General Motors about 1.5 years later. They were happy to find someone with coach experience, of course I never did work on any coaches, all trucks.
Voyageur Colonial was the largest intercity bus line in Central Canada, in the ’70s and ’80s. And the GM Buffalo, was a backbone of their fleet. Travel on the busy 401 linking Toronto and Montreal, or the Trans-Canada Highway between Toronto and Ottawa, and you would see countless Buffaloes. At all hours. I rode them many times as a teenager, and student. I used to catch a 10:30pm bus every Sunday night back to Ottawa, in truly bone-chilling frigid weather, and the Buffaloes were always on time, and warm inside.
Paul Bateson documented hundreds of Voyageur buses during that era, and has posted vintage pics at his Flickr page. Including many Buffaloes.
https://www.flickr.com/search/?user_id=60257481%40N04&view_all=1&text=voyageur
The tiniest remote gas stations or diners served by Voyageur, would have a sign indicating tickets could be bought there, and buses would stop. The Buffalo was the bus depicted in their signage through the 70s and 80s. A common sight in the smallest villages in Ontario and Quebec, served by the company.
Had a look at the Bateson pics – quite surprised to see the Neoplan. Was this is one-off or did they have more than one example?
I noticed it as well. On the rear flank, you can see the logo of ‘Transport Canada’, so it would have been a trial of the Neoplan for the busy Montreal to Toronto route. Subsidized, by the Canadian government. It appears only the one bus ‘no. 500’, was tested during the Fall of 1980. From the late 60s until 1982, Canadian National ran the high speed gas turbine UAC TurboTrain between Montreal and Toronto as well.
The other articulated bus Mr. Bateson photographed, was the failed Prevost H5-60. Profiled at CC: https://www.curbsideclassic.com/bus-stop-classic/bus-stop-classic-prevost-h5-60-1988-1992-youre-going-to-need-a-biggggg-parking-space-for-that/
Very interesting article, especially hearing from drivers and mechanics like xr7. The GMC school buses I rode in during the 60s and 70s were manual. I knew a little bit about manuals, and wondered why the driver would let the clutch out then press it back in again between gears. Then I learned about double clutching. Somewhere there was a post here about not using the clutch, instead do re-matching I think. Could that Spicer 4 speed be shifted like that? I’d expect that would take a lot of practice, but so would double clutching.
I wonder if 4th gear in the manual was 1:1 direct drive or overdrive? I like manual transmissions, have one now, but can imagine driving a non-synchronized bus in the city could be tough. Interesting those (2 speed?) automatics were available as early as 1948. I’ve heard those Allison automatics referred to as 1 speed, the torque converter in line up to about 30 mph or so then bypassed and in direct drive. I saw mention of a 3 speed automatic in this article, probably used for highway coaches.