with universal acclaim. In its September 1966 issue, Motor Trend summed it up well: “Ford’s Bronco with its standard 6-cylinder engine is quite capable of unseating an unstrapped rider in somewhat less than the standard rodeo time of 8 seconds. But now with an optional 200-hp, 289-cubic-inch V-8, it packs the violence of a Braham bull … 200 hp feeding into a 4:57-ratio limited slip differential is somewhat akin to whipping water in a Waring blender.” The 289 offered the option of either a paper air filter or an oil-bath air filter.
Motor Trend testers were quite exuberant in their appraisal of the new Bronco V-8 in the September 1966 issue. You can only imagine what the landing was like when the little bobtail half cab returned to terra firma. (Photo Courtesy Motor Trend Group, LLC)
The 289 V-8 was introduced in the Bronco lineup in March 1966, immediately vaulting the Bronco to the top of the horsepower list in the segment. The 1966–1968 V-8 Broncos, in their original configuration, had sealed radiators with an expansion reservoir tank with a cap mounted between the radiator and the engine. Many of these tanks have been discarded. (Photo Courtesy Tim Hulick)
Transmission
The 1966 Broncos used 3-speed manual transmissions with a shifter mounted on the column, a configuration used on the F-Series pickups at the time. Because the remainder of the segment vehicles used floor-mounted shifters, Ford touted the column shifter as a plus that gave more seating room for front-seat passengers. Consumer reaction was mixed, and Hurst introduced a floor-shift conversion within a year of the Bronco’s introduction that proved to be very popular with Bronco owners for many years.
The 6-cylinder 3-speed, known as the RAN, had ratios of 3.41, 1.86, and 1.00:1. When the 289 V-8 was introduced, an almost identical transmission with slightly higher torque capacity, known as the RAT, was used. First and second gears had slightly higher (lower numerically) ratios of 2.99 and 1.75:1. Because the engines were different lengths, the cast-iron adapters were of differing lengths so the transfer case and transfer case crossmember could stay in the location in the vehicle regardless of the engine and transmission.
Recently, a retired Ford engineer revealed in an interview that he was responsible for the redesign of the adapters after the initial configuration failed during testing right before the vehicle’s introduction. The engineer noted with a wry smile that he received “lots of help” in the redesign.
The 6-cylinder 3-speed transmissions were backed by a 9-inch-diameter clutch with a 9.375-inch unit as a heavy-duty option. The 289 3-speed had an 11-inch clutch between it and the engine.
Transfer Case
In choosing the Dana 20 transfer case for the Bronco, Ford selected one of the best transfer cases ever used in 4WD vehicles. This transfer case, which featured a cast-iron housing and used steel gears (not chains), enjoyed a sterling reputation for longevity and strength; Jeep specified it for its J4000 1-ton trucks.
Ford learned from its preproduction surveys that customers wanted quieter drivetrains on their 4WDs. The Spicer 18 transfer case, which had been used in Jeeps since their introduction and in Scouts until 1965, was a so-called “offset design” (the input and output shafts were not colinear), requiring an intermediate shaft and gears as part of the power transmission from the input shaft to the output shaft. The extra gears generated noise, particularly at highway speeds, which consumers found tiresome.
The Dana 20 was a “straight through” or “silent drive” design, highly touted at the Bronco’s introduction. Because the input and output shafts were colinear, there were no gears moving in the transfer case when operated in two-wheel drive (2WD), resulting in much less gear train noise. And although the Scout 800 had started using the Dana 20 in 1965, the International Harvester unit had a low range ratio of 2.03:1, compared to the 2.46:1 low ratio of the Bronco Dana 20, which was much more desirable for those enthusiasts looking for the lowest possible crawl ratio.
The mid-1960s was also a time when manufacturers were moving from the twin-stick transfer case shifters to single sticks to make shifting into 4WD less confusing and intimidating for first-time 4WD owners. Jeep had made the jump to a single-stick transfer case in its CJ-5 with the introduction of the 225-ci V-6 engine in 1965, and Ford followed suit with the Bronco (its F-Series 4x4 pickups always had them).
The single transfer-case shifter found on the 1966 Broncos is a textbook example of engineering revisions during production as customer feedback revealed weaknesses.
The initial shifter design was a single lever topped with a traditional shifter knob denoting the shift pattern, similar in design to the shifters used in other vehicles but longer in length, presumably to ease shifting effort. Several testers in early magazine reviews noted that the resulting shifter position was very close to the column-mounted transmission shifter when it was in third gear. Four Wheeler, in particular, noted that the shifter knob tips were less than an inch apart, and they feared that a driver may inadvertently shift into 4WD high.
International Harvester, in a period document that compared the Scout to the Bronco, noted that there were reports of the Bronco shifter breaking off at the transfer case due to the increased leverage of the long lever. The obvious agenda of a competitor’s document notwithstanding, broken shift levers were reported by other 1966 owners.
Apparently, Ford listened to these complaints and later production models used a shorter version of the same shifter. Late in the model year, coinciding with the introduction of the V-8, Ford made a switch again to a shifter topped by a chrome T-handle. The handle housed a push-button assembly that actuated a gated plate at the base of the assembly to lock the shifter into the specific gearing options in the transfer case.
These first T-handle shifters had boots similar to, but larger than, the first-generation 1966 shifters. The driver still had to rely on the shift-pattern decals on the dash to determine exactly what gear the transfer case was in, and it likely took some time and finesse for owners to figure this out. The base of the shifter was modified as well with a stronger configuration that worked well for the next six model years.
Ford used double Cardan U-joints at the transfer end of the front and rear driveshafts in the Bronco. This allowed the transfer case to be mounted higher inside the frame for additional ground clearance.
Axles and Suspension
Although Ford used solid axles front and rear on the Bronco, as did other 4WD manufacturers in the 1960s, the outboard ends of the front axle were revolutionary at the time. According to Axelrad’s SAE paper, Ford originally planned to use a Dana 27 closed-knuckle axle (used by CJ-5 and Scout) but decided to go with the Dana 30 front axle instead when it learned of its upcoming release.
Dana 30
Dana promised 500 pounds more capacity than the Dana 27 with the Dana 30 through the use of thicker walled, larger tubes. The 2,500-pound capacity rating fit neatly between the competition (2,000 pounds) and full-size pickups (Dana 44 with a 3,000-pound rating). More important, it featured the industry’s first open-knuckle design, which allowed much tighter turning angles than its closed-knuckle cousin (37 versus 29 degrees). Axelrad noted that the full advantage of the Bronco’s coil-spring front suspension could not be realized without the use of the open knuckles due to the steering angle limitations of the closed-knuckle design.
The 1966–1967 locking hubs were optional ($66.08), and they are unique to those years. In 1968, Ford switched to a bright housing with a red dial.
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