This is a 1970 GM “Buffalo Bus” that was converted into a motorhome over the course of a 10 year rebuild in Connecticut. It’s now a fully-equipped home-on-wheels, and it was featured on the cover of Bus Conversions magazine.
Inside you’ll find red oak cabinetry, Berber carpets, and bison-themed trim, with a lounge area fitted with a convertible leather sofa and folding dining table. The kitchenette includes a two-burner glass cooktop, convection microwave, refrigerator, and a bathroom which has a shower, toilet, and sink. At the rear, a queen bed with a memory-foam mattress sits beneath mirrored cabinets along with a television.
Fast Facts: The GM Buffalo Bus
- The GM “Buffalo” bus series was introduced in 1966 by General Motors’ Truck & Coach Division as a successor to its earlier PD-4104 and PD-4106 coaches. Built in Pontiac, Michigan, these buses featured sharper styling, a split-level interior for improved luggage space, and Detroit Diesel 8V-71 engines producing 315 bhp.
- Offered in multiple versions including the PD-4107, PD-4903, and later PD-4108 and PD-4905, the Buffalo lineup evolved through the 1970s with upgraded electrics, modular construction, and automatic transmission options. Despite its clever innovations, competition from MCI and rising fuel costs caused GM to end production in 1980, marking its exit from the intercity coach market.
- The 1970 GM PD4108 shown here started as a 35 foot coach for James River Bus Lines in Virginia before undergoing a 10 year motorhome conversion in Connecticut. Completed in 2004, it was featured on the cover of Bus Conversionsmagazine and is one of roughly 70 examples of its model built during a brief two-year run.
- The motorhome’s hand-built interior has red oak cabinetry, Berber carpets, and bison-themed décor, with a lounge, kitchenette, bathroom, and rear bedroom. It’s powered by a 9.3 liter Detroit Diesel V8 mated to an Allison V730 automatic, equipped with a 10 kW Kubota generator, dual roof A/C units, and ample water storage tanks, currently offered for sale at no reserve.
History Speedrun: The GM Buffalo Bus
General Motors introduced the “Buffalo” series of intercity coaches in 1966, they were conceived as a replacement for the celebrated PD-4104 and PD-4106 coaches – buses that had set the standard for long-haul travel in the 1950s and early 1960s.
General Motors introduced the “Buffalo” series of intercity coaches in 1966, they were conceived as a replacement for the celebrated PD-4104 and PD-4106 coaches – buses that had set the standard for long-haul travel in the 1950s and early 1960s. Image courtesy of the General Motors Truck & Coach Division.
By the time the Buffalo arrived, however, the market was changing fast. Greyhound, once GM’s biggest customer, was shifting its purchases toward the newly independent Motor Coach Industries (MCI). In some respects, the Buffalo was GM’s final attempt to modernize its coach lineup and hold its ground.
The Buffalo name came from GM’s Truck & Coach Division, and the series was built at the Pontiac West Assembly plant in Pontiac, Michigan from 1966 until 1980. The first production model, the PD-4107, was a 35 foot, 96 inch wide coach that introduced a new styling direction. The design moved away from the rounded “fishbowl” look of earlier coaches for sharper, more contemporary lines. The deeply recessed headlamps and flared beltline gave the bus a distinctive, almost automotive appearance.
Power came from the Detroit Diesel 8V-71, a two-stroke V8 engine producing approximately 304 to 318 bhp, mated to a 4-speed Spicer manual or an optional automatic transmission. The layout was a rear-mounted V-drive, as with previous GM coaches, but the Buffalo used a split-level interior design to improve luggage capacity while keeping as much passenger headroom as possible.
This bus could seat 41 passengers in highway trim, with options for air conditioning, restrooms in the rear, and air suspension systems that notably improved ride quality.
In 1968 GM introduced the PD-4903, this was a 40 foot version that offered more seating capacity, and as a bonus, slightly improved weight distribution. The 4903 kept the 8V-71 powerplant but used a more complex cooling system and optional tag axle to support the extra length. The two models ran concurrently for a number of years, with Trailways and other intercity operators among the main buyers, by this time Greyhound had begun shifting to MCI-built coaches.
A year later in 1970 came the PD-4108, this was an evolutionary update with a series of subtle improvements to interior layout, wiring, and sound insulation. The PD-4905, which launched soon after, replaced the 4903 and represented the high point of Buffalo development.
This 1970 GM PD4108 Buffalo Bus began life as a 35 foot motorcoach for James River Bus Lines of Blackstone, Virginia, before being converted into a luxury motorhome over a decade-long project in Connecticut.
The 4905 continued with the V-drive layout and Spicer manual gearbox, though there were some automatic options introduced later. Many 4905s were built with factory air conditioning, improved heating systems, and panoramic passenger windows as they were intended for cross-country trips.
This was a time when low-cost commuter jets were nowhere near as common as they are today, and the niche was largely filled by Greyhound and the other cross-country and intercity bus services.
In 1972 the line received a mid-life update that replaced the old “PD” prefix (for Parlor Diesel) with “P8M” and “H8H” designations – denoting powertrain and model differences. The P8M-4108A and P8M-4905A continued the core formula but used modular construction techniques and improved electrics.
The final variant, the H8H-649, was produced from 1979 to 1980 as GM’s last Highway-series Buffalo, offering either the Spicer 4-speed manual or an Allison automatic transmission option – it was purchased by several US and Canadian regional carriers, including Grey Goose and SMT Eastern.
Despite its constant series of updates and innovations the Buffalo struggled to maintain significant sales. The shift in market dynamics, combined with rising fuel costs and GM’s waning interest in the intercity coach sector, led to declining production numbers through the late 1970s. The Buffalo was quietly discontinued in 1980, forever ending GM’s intercity coach production.
The GM Buffalo bus represents a turning point when design, technology, and market forces collided at the end of America’s golden age of highway travel. It was both a successor to the legendary Scenicruiser and a swan song for General Motors’ coach-building division, closing one of the most influential chapters in North American bus history.
The aluminum body was media-blasted, fitted with 18 gauge steel window panels, and refinished in pearl-effect white and silver with red and black striping. A Zip Dee awning and airbrushed artwork were added, while polished 22.5 inch wheels wear Toyo M170 tires.
The GM Buffalo Bus Motorhome Shown Here
This 1970 GM PD4108 Buffalo Bus began life as a 35 foot motorcoach for James River Bus Lines of Blackstone, Virginia, before being converted into a luxury motorhome over a decade-long project in Connecticut.
It was completed in 2004 and later featured on the cover of Bus Conversions magazine, it’s one of roughly 70 PD4108s built during a two-year production run. The conversion included a reconfigured interior with a lounge, kitchenette, and bedroom with an ensuite bathroom.
The aluminum body was media-blasted, fitted with 18 gauge steel window panels, and refinished in pearl-effect white and silver with red and black striping. A Zip Dee awning and airbrushed artwork were added, while polished 22.5 inch wheels wear Toyo M170 tires.
Equipment includes Sheppard power steering, air brakes, and modified luggage bays containing a sliding storage drawer, Webasto furnace, 10 kW Kubota generator, Trace 4000W inverter, and eight deep-cycle batteries. Two rooftop air-conditioning units serve the living space, with fresh, gray, and black water tanks of 110, 85, and 65 gallons respectively.
Inside, the coach has red oak cabinetry, Berber carpets, and bison-themed décor. The forward lounge includes a convertible leather sofa and folding table, the kitchenette offers modern appliances and tile flooring, and the rear bedroom houses a queen bed with an 8 inch memory-foam mattress. The bathroom has a shower, sink, and toilet separated by latching closet doors.
Inside, the coach has red oak cabinetry, Berber carpets, and bison-themed décor. The forward lounge includes a convertible leather sofa and folding table, the kitchenette offers modern appliances and tile flooring, and the rear bedroom houses a queen bed with an 8 inch memory-foam mattress. The bathroom has a shower, sink, and toilet separated by latching closet doors.
Power comes from a 9.3 liter Detroit Diesel V8 paired with a retrofitted Allison V730 3-speed automatic transmission. The six-digit odometer shows 89,000 miles, about 9,000 added by the current owner since 2017.
It’s now being offered for sale at no reserve on Bring a Trailer with a clean Missouri title out of Springfield, Missouri and you can visit the listing here if you’d like to read more about it or place a bid.
Images courtesy of Bring a Trailer + the General Motors Truck & Coach Division
Articles that Ben Branch has written have been covered on CNN, Popular Mechanics, Smithsonian Magazine, Road & Track Magazine, the official Pinterest blog, the official eBay Motors blog, BuzzFeed, Autoweek Magazine, Wired Magazine, Autoblog, Gear Patrol, Jalopnik, The Verge, and many more.
Silodrome was founded by Ben back in 2010, in the years since the site has grown to become a world leader in the alternative and vintage motoring sector, with well over a million monthly readers from around the world and many hundreds of thousands of followers on social media.
