GMC Models & Transmodes


In Las Vegas in January 1974, GMC announced a new series of vehicles for commercial, medical, and general transportation purposes, and nine Transmode concept vehicles were shown to the press. An Eleganza SE (RPO#696) "featuring customized interiors much more luxurious than those in current models" was displayed as well. This was the start of Alex Mair's plan to make the GMC Motorhome the "Cadillac of motorhomes." He had made the comment at one point that the GMC Motorhome was to GMC what the Corvette was to Chevrolet, its halo (image) vehicle.

GMC, now offering a motorhome rental program, conducted a fuel economy run with press representatives from Automotive News, Motor Trend, and Trailer Life magazines. A motorhome economy run could be very risky, and some reporters noted that GM should get the "sheer courage award" and had "corporate guts" to propose an economy run on a 23-foot motorhome during the gas crisis. Over a 264-mile test from Los Angeles to Las Vegas, which included the well-known Baker Grade, which peaks at 4,751 feet, the reported mileage was 10.2 mpg using cruise control most of the way. The return trip provided an 11.2-mpg average, since this direction was slightly more downhill. Evidently, GMC was trying hard to revive sales during this period of gas shortages.

Motorhomes were conveyed sideways on dollies along the interior finishing line.
In March 1974 GMC announced that it had suspended production once again due to a lack of orders. Gemini still had a backlog of shells to upfit, but scaled back to a one-shift operation. Sales began picking up over the next couple of months, and by midyear inventories were depleted and production was resumed.

The 1975 model year brought many changes to the GMC Motorhome. New model names were announced; Eleganza II and Palm Beach replaced the previous models. New, better-quality woven fabrics supplanted the printed fabrics that had been used in earlier coaches, and Flexsteel seating was installed. Assembly of interiors at Gemini was discontinued, and all of the interior upfitting was brought in-house at the Pontiac plant (none of the Gemini employees were picked up by GMC for the in-house assembly). Grand Rapids Furniture Co. was now building the interior modules, and dovetail joints replaced glue and staples. While the quality of the interior fittings improved measurably, heavier weight and higher cost of the furniture was the downside. Exterior changes included new colors and stripes; exterior paint was now urethane (Imron) instead of the previously used synthetic enamel; raised "GMC" letters replaced vinyl decals on the motorhomes; and the fit and function of exterior panels and doors were improved, as was the floor substructure. Stronger frame cross members were added; new Hehr side windows were installed; an HEI ignition system was added; and polybutylene (plastic) plumbing replaced copper. Gross vehicle weight ratings were increased to 11,700 pounds, and many other changes and improvements were incorporated as well.

The Transmode, an "empty motorhome" for those who wanted to build their own interiors, was available from 1975 through 1978. GMC no longer offered the 23-foot unit as a motorhome, although it could still be purchased as a Transmode and upfitted by others.

On dollies along the interior finishing line; these particular photos were taken in 1975.
Many companies were upfitting the new Transmode as motorhomes and for commercial applications. Some of the motorhome upfitters were Avion, Coachmen, Carriage, LRP, Midas, Norris, Hughes, Landau, Roll-a-long, El Dorado, Foretravel, and Winnebago, plus a few others with very low build quantities.

Transmode upfitters for commercial purposes were many. These GMCs were used as ambulances/emergency vehicles, bookmobiles, mobile banks, airport shuttle buses, mobile showrooms, on-location radio broadcast centers, hearses, courtesy coaches for beer and soda distributors, and much more.

The 1976 GMC Motorhome models arrived with few changes from the previous year. Two new models were introduced in addition to the Eleganza II and Palm Beach carryovers: the Glenbrook and Edgemont. The Edgemont was the price leader with a base price about $1,000 below the other three models. Running changes continued to be made, most starting with serial number 6V100878. They added an entry door strap; relocated the air compressor and solenoid valves to an inside compartment (Electro Level); and added a glass-lined hot water tank, cab floor support (stamping), radial tires/wheels, and body side rub molding (with adhesive replacing stainless).

In 1977 the Kingsley model debuted, replacing the previous year's Glenbrook model. The Eleganza II and Palm Beach continued to be offered. The Edgemont was replaced by a new twin bed/dry bath floor plan in the Eleganza II. Other changes included a redesigned dash, which relocated the AC/heater outlets and moved the Electro Level controls to the left of the driver; a new Freedom battery; an entrance door rain cap; and an assist handle.

Another model, the Coca-Cola, was built in two versions. The first was the "standard" model, offered in cameo white with a red horizontal stripe, the same pattern as other GMC Motorhomes. It is believed these motorhomes were used primarily by Coca-Cola bottlers and distributors as courtesy coaches and at public events. The second Coca-Cola model was dubbed the GadAbout and equipped with all the bells and whistles. The exterior paint was white with a sweeping wedge of Coca-Cola red up the sides that blended to a yellow near the top rear of the coach. The GadAbout name appeared near the front, and a bottle-cap-shaped spare tire cover was at the rear.

The Coca-Cola model was built in two versions.
Inside, the Coca-Cola red upholstery was the same in both coaches. In the GadAbout, refrigerator door graphics made the appliance look like a sodadispensing machine — very impressive! Other extras were a Coca-Cola logo entry floor mat, clock, and mirrored picture, as well as a rear table with a Coke checkerboard pattern. On the dash above the glove box was an attractive pewter plaque with a GadAbout motorhome in profile and the slogan, "Coke adds life to . . . cruisin' in a GadAbout."

Five GadAbouts were given away to first-prize winners of a Coca-Cola contest held in December 1977. Twenty-five second-prize winners each received the use of a GMC Motorhome for two weeks along with $3,000 in cash. GMC records indicate that a total of 55 Coca-Cola models were built, most in 1977 and a few in 1978. It was originally believed that only five of the total were GadAbouts; however, more have been discovered lately, and as many as nine or 10 may have been built.

The 403-cid engine replaced the 455-cid engine by the end of January 1977 and was used for all remaining motorhome production. GM's downsizing had started and would soon have severe implications for the GMC Motorhome.

Plant No. 3 in Pontiac, Michigan, had been the site of GMC Motorhome production from the beginning in late 1972 through mid-1977. In August 1977 production was moved to Plant No. 29, also in Pontiac. This site provided a more efficient production facility and was used through the end of production in 1978.

On November 11, 1977, Robert W. Truxell, general manager of GMC Truck and Coach, announced the phaseout of GMC Motorhome and Transmode production (see the accompanying sidebar for the text of the announcement). According to the GMC engineers I have spoken with, no advance warning was given to the employees, and they were surprised at the news. In all probability, it should not have been too surprising. Carrying too much burden and overhead and never reaching the volumes needed to achieve real profitability, GM saw better ways to use its resources and achieve greater return on its investment.

The 1978 model year began with three models of GMC Motorhome interiors: Eleganza II, Palm Beach, and Kingsley. Production of the Transmode continued as well, with many upfitters participating. The major upfitter was Coachmen Industries (Jimmy Motors), producing the Royale (26-foot) and Birchaven (23-foot).

New GMC Motorhome two-tone body colors and a three-color horizontal midbody stripe distinguished the 1978 models from other years. A number of features that were options in previous years were now standard, and many features were improved. Improvements included the Electro Level II, a larger bathroom skylight, a 36-gallon holding tank, integral refrigerator vents, new solid cupboard doors, new countertops, and woven window blinds. Chrome bumpers were finally standard. Among the new options were a glass and spice rack, a microwave oven, an overhead rear cabinet, a six-speaker sound system, a lighted visor vanity mirror, and a lockable overhead front cabinet.

On the Transmode, urethane foam floor insulation, previously an option, was now standard. The steering wheel, column, and hand brake were now saddle-colored, and the front-end GMC logo was now displayed in raised lettering instead of a decal.

With the end of production approaching, plans had to be made to phase out production in as orderly a manner as possible. Build-out plans were made, i.e. matching parts inventories to dealer/customer orders. One example of this was the sale of surplus transmissions and final drives by GM to an Ohio GMC Motorhome dealer who purchased 1,361 units. These were initially offered at a sale price of $495 each (the suggested list prices were identified as $1,375 for the transmission and $675 for the final drive). When the inventory got down to 500 units, the sale price was reduced to $475. In 1983 the price was reduced again to $295, at which time the remaining inventory was sold. GMC Motorhome and Transmode production ended in July 1978.

A 1974 press release package showed cutaway views of the GMC Motorhome
That being said, the rest of the story is as follows. An important consideration should be that Alex Mair, a very strong advocate for the GMC Motorhome, had gone to the Pontiac Division, and there was no one willing to fight for the program. There were, of course, other serious and obvious concerns with the program that needed to be resolved. The Oldsmobile engine and drivetrain would soon be gone from the Oldsmobile lineup due to GM's downsizing efforts. GMC would either have to build this unit on its own or design a new one involving new tooling and development expenses. Sketches of a rear engine/rear drive and front engine/front-wheel drive (using a transfer case) exist. A front suspension using a solid front axle and single leaf springs with an air spring at the center, similar to the RTS bus design, was proposed. Apparently, one operational prototype of a transverse front engine/front-wheel-drive motorhome was built. None of these redesigns would support a business case. Motorhome build quantities were just too small to end up with positive results and, finally, the decision to terminate production ended all further development efforts.

GM announced additional details over the next few weeks. The GMC Motorhome Club, supported by GM, was discontinued, and in its place a new organization, GMC Motorhome Owners Association (GMC MOA) was formed. GM noted that it was independent and separate from GMC Truck & Coach.

GMC attempted to sell the GMC Motorhome assets for a reputed $7 million to another manufacturer that would continue production. AM General, a Division of American Motors, took a look and built five prototypes using a 454-cid engine, with a transfer case to turn the drive back to the new front axle, much like Revcon actually did in subsequent years. On the inside, the front steps to the driving compartment had to be modified to allow additional room for the transfer case. This was as far as it went for AM General. After some testing, company officials decided not to pursue the purchase of the GMC Motorhome.