Slate's "GMC Motor Home" Homepage

This page covers the 23 & 26 foot motor homes made by GMC from 1973 thru 1978. This is not a commercial page and at this time I'll attempt to avoid conflicts with all related GMC MH suppliers. Since nobody is paying for this I provide no warrenty and the user (you) accept all risk in using this information.

Great effort is made as to the appropriateness of remote links but I can not be responsable for other's homepages. Additions, corrections and deletions are welcome and will usually be applied the same day as I become aware of them. If HTML or other errors are found, please let me know. Support is intended back thru Netscape 2.0 and Windows 3.1

For quicker downloading most photos and greater details are provided with links indicated by standard html highlighting.


Detailed Description

For those owners of other brands and those who do not 'know' the GMC here is a brief discription.

These GMC coaches were delivered in both 23 and 26 foot lengths from 1973 thru 1978. They were built on the GMC coach (bus) assembly lines and came in both the motorhome version which was finished by other motorhome companys and a Transmode version. The Transmodes often were used as airporters, radio stations and mobile banks among other things but most have since evolved to motorhome use. Because these coaches are front wheel drive, the chassis (frame) could be centered between the wheels rather than above the suspension componets and drive line. This allowed for a lower and more stable vehicle (at the expense of underfloor storage).

The engines and transmissions were derived from the current model year Oldsmobile Toronado and share both the drive line and a surprising number of suspension and steering componets. The earlier units having the 455 ci engine and the later units the 403 ci engine, both equipped with the Toronado 3-speed (Hydramatic 425) automatic transmissions.

Like the Toronado, the front suspension is twin A-Arms sprung with torsion bars running back under the front seats (near the ground). The rear suspension is what I call a 'bogey' type. Each side has two semi-independent rear wheels. The front bogey supported with a leading link and the rear bogey with a trailing link, very simalar to the trailing link on a motorcycle. Between the two is one air bag that acts as the spring. Air pressure is provided by a 12 volt powered one or two cylinder air compressor and is adjustable from the drivers position or automatically as road conditions demand. Since the air bag is mounted between the bogeys, not to the frame, road noise is greatly diminished as is the tendency for the vehicle to rock. This is no more apparent then in the sales lot when one steps into a GMC after being in some other SOB (some other brand). It's actually hard to make a GMC rock.

As the bogey assemblys mount to the outside of the frame rails no suspension componets cross the width of the coach except the front sway bar.

The frame rails are about 7 inches tall and the exhaust system is routed down the inside of the passenger side frame. The coach is mounted directly above the frame and the waste water tank and both 25 gallon fuel tanks are mounted between the frame rails. The fuel tanks are plumbed as one tank and only one filler is used although the plumbing scheme provides for about 5 gallons of reserve fuel to be available from either tank.

The body is constructed of a blend of aluminum and fiberglass. Typically the large flat panels are aluminum and the areas with compound curves are fiberglass. Other than the vehicle chassis (the frame) which is steel, all of the coach frame is aluminum. The firewall is aluminum as all areas requiring metal structural sheets. No structural wood is used anywhere except in the floor which is made rigid with 3/4" plywood, which is clad on the exterior in aluminum for weatherproofing. The roof is one piece of aluminum on aluminum structual members. These GMCs are very solid.

Only one door is provided on the GMC although in the movie Twister, that GMC has a driver's door! On the 23 foot unit the door is behind the passenger front seat while on the 26 foot unit it is somewhat further back. Unlike most other brands the floor sits very close to the ground. Although no step were provided by GMC, some owners have added one. Consider that next time you climb into a modern RV. Probably only the Vixen Motorhome has a lower floor.

The GMC has windows, lots of BIG windows. Ours has a couch behind the drivers seat, the back of which can be lifted and attached to the ceiling providing a suspended bed with a bed below it. Behind the passenger side front seat is a four seat dinette which also makes into a bed. Behind the dinette is the door. The 12 vdc compressor type refrigerator is next with the central vaccum system installed under the fridge. Next is the bathroom with shower, the electric water heater (assisted with a engine heat exchanger) being installed under the bathroom sink. At the rear of our GMC is the master bedroom with the propane tank and fresh water tank mounted on the rear of the right side of the vehicle. The rear bed makes into a dinette type area but most owners always keep it set up as a bed using the area under the bed for storage.

Behind the bunk bed on the drivers side is the kitchen counter, sink and gas stove with microwave oven with the gas furnace mounted under the counter. Then we have dresser type drawers with the air compressor system and a high current 12 vdc power supply/charger and the 130 vac, 40 amp circuit breaker panel in the bottom drawer area. On the rear left (drivers) side is mounted the ONAN 6 kw generator set and a very large storage battery (4D) that provides coach power when other power is not available.

All lights, fans, the water pump, furnace and refrigerator run on 12 volts DC, only. The only items that don't run on 12 volts DC are the microwave oven, the regular oven's electric warmer, the water heater and the roof mounted air conditioner. (In reality the refrigerator uses a 36 volts ac compressor but the power still comes from the 12 volts DC thru an invertor. The refrigerator does not have to be level to operate!)...return to index

Problems & Solutions

This may appear to be a lot of problems. Keep in mind the age of the vehicle and the total miles. Also note that we usually tow either a heavy boat, a car or a jeep, often thru the Rockys and on lots of dirt roads. Comparitively, I don't feel we see any more problems than I would with a modern coach that has seen the same service. Note that the repair parts prices are reasonable, very reasonable compared to that of modern vehicles.

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Dumb and Good Ideas

(contributions requested, especially for dumb ideas!)

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GMC Owner Homepages, Not For Profit

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GMC Owner Resources, Not For Profit, Clubs

Unless requested, not for profits will be listed without phone numbers. E-mail me for changes.

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GMC Owner Resources, Commercial

Unless requested, commercial resources will be listed with phone numbers, the numbers have not been verified. E-mail me for changes.

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Units & Items For Sale or Wanted

While providing links is under my control the information in these links often is not. If you find any listing that is improper, in error or would like to list or un-list something, let me know via ''.

No items listed

I suggest that you look in the Owner Homepage area also.

Wanted: Just Dreaming

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Our GMC & Some Trips

As of September of '96 we are the new and very proud owner's of a 1977 26' GMC. Although the pink slip calls our GMC a 1978 the plate at the door says 1977. We therfore call it a 1977 GMC. David with the registry tells us that it is a Kingsley model, which I agree with.

When we bought our GMC it indicated 51,000 miles. The owner made statements that make me think it really had 151,000 miles. The condition of the coach makes it hard to believe it has travelled that far but that is a statement as to the quality of the GMC's. The owner also said it had visited all 48 of the lower states, some of Canada and quite a bit of Mexico. As of today she has about 191,000 miles. She's a little more tarnished but still quite proud, as are we of her.

  • Link to our Travel Pages

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    Vixen Motorhome Stuff

    A Vixen is a unique motorhome like the GMC. If I wanted a smaller highway burner that got 21-33 mpg for just one person, maybe two, this is what I'd look for... $18,000 to $32,000 range, 1986-89.

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    Credits & Host Contact

    created and maintained in DOS with a text editor
    created 31 Dec 96
    last edited 18 May 2006, Added Projects Link
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