CONVOY's Rubber Duck
Many truck enthusiasts incorrectly think that this Mack had a Detroit Diesel Engine for power. The Detroit sound heard from the Mack throughout most of the movie is a combination of studio overdub, the sounds of the unit pulling the prop-Mack glider and the sound of one of the 1972 Mack's which was equipped with a Detroit Diesel 8V-71T. The tell-tale on this 1977 Mack is the Tip Turbine dual tube air cleaner. That air cleaner was ONLY used on Tip Turbine equipped Mack's. A similar, but somewhat different dual tube air cleaner is still available today on the RD series, but is built for inside/outside air intake switchability. See the RS700L Hood page for photos and more details.
Photos of the 1972 Mack are shown below. Again, notice the different frontal appearance of the hood and bull bar, as well as the single intake tube on the air cleaner. Additionally, you can see the different spacing on the air cleaner straps. The ETAY air cleaner straps are spread farther apart than the tightly spaced straps on the other air cleaners. This truck shown below had the Cummins 350 and was the truck bought by Bruhn after filming.
The inconsistencies in various scenes are very confusing. Even after hours of study of the movie, there still is no clear-cut reason other than mutliple takes of the same scene with different vehicles. The two major scenes that used multiple copies of the Rubber Duck's Mack are the Jail sequence and the Bridge sequence.
In the jail seqence, the 1977 RS786LST was used for the approach side by side with Pig Pen's Cruiseliner. In still or slow motion, it can be clearly seen that a reflective protective covering is placed in front of the windshields of both vehicles.
In slow-motion still shots, it can be confirmed that the 1977 RS786LST was used in the initial hit to the jail wall or a full-heighth mock-up of the wall.
But, the interior shots at the jail show a very unique Mack that only appears again as the Mack that falls from the bridge. This Mack is well worn, and features what appears to be a brush painted black coat of paint on the cab, a single intake air cleaner, a straight stack (no muffler) and all of the "chrome" parts are painted silver.
When the Mack backs out of the jail, another unique truck is seen, this time using a pre-73 chassis with a post-73 hood. This Mack features the unique stirrup and extra step box behind the fender, very short fuel tanks and a large sleeper other than the Able Body Co. sleeper on the other Macks. Also, you will notice that the muffler reappears, the air cleaner changes again and features no rain cap and the hood is cracked along the top midway back on the driver's side.
When the Mack is pulling out of the station, we see that the muffler has reappeared and note that the fuel tanks are much shorter. Additionally, the air clean has no rain cap and is of a single intake type. The hood features a large crack on top midway back on the driver's side, and the stirrup and pre-73 step box are shown behind the fender of a post-73 hood.
There were a total of 5 Mack's used to represent RD's truck throughout the movie. The 1977 was the one most commonly seen in the movie, but there were 2 1972's used as well as a glider mock up and a cut-away used for close up scenes. The most specs for the 1977 are:
Model: 1977 Mack RS786LST
Engine: Mack ETAY676 283 hp "Tip Turbine" turbocharged inline 6 cylinder diesel
Transmission: Fuller RT9510 10 Speed Roadranger
Wheelbase: 220" Center of Front Axle to Center of Tandems
Sleeper: 60" stand-up sleeper by Able Body Company w/right side exhaust cut-out
Suspension: Mack 38,000# Camelback
Rear Axles: Mack 38,000#
Wheels: "budd" style 10R22 tube-type black painted steel w/2 hand holes.
This truck was "new" when filming began. It was provided thru a Mack Dealer new Albequerque, NM, and was custom fitted with a bull bar and high-set fifth wheel to accomodate the Fruehauf Tank Trailer. This truck was used for most of the "still" shots and on-highway scenes in the movie. The truck's condition was altered and battle scarred for scenes shot early on which represented a later timeframe in the story board. This unit was damaged in the collision with the stalled patrol car outside of Albequerque and in some re-filming of the damage to the Alvarez Jail. The final film sequence for this unit was the approach to the bridge scene and SOME of the frontal gunshot hits. This unit survived production and was rumored to be in a vehicle museum.
The 1972 Mack used as the second operating unit featured a NTC350 Small Cam Cummins and a Fuller 13 speed transmission. After filming, this truck was purchased and used by Fred Bruhn in his aggregate business until 1988 when it was totaled in a roll-over. It should be noted that Fred Bruhn's trucks were used throughout the movie. See "Other" Trucks for more information.