The tractor’s HydroPower system was a notable development
IN THE SHOP with Rachel
By Rachel Gingell
The Oliver 770 was produced from 1958 until 1967. Exact production numbers are disputed by collectors but conservative estimates put the production at 100,000 tractors or more. The 770 was a popular model in the line at the time and is still favored by Oliver enthusiasts.
Parts for these tractors are plentiful and inexpensive due to the large amount of interchangeability between the 770 and other models. The 770 is an upgraded Super 77 (which shares much in common with the 77).
The slightly smaller Oliver 550 shares many design elements with the 770 as well. With an 18-year production run for the 550, there are plenty of tractors around to keep companies supplying parts for these tractors for years to come.
The 770 came with the variants you’d expect in a well-rounded model of the era: wheatland, high crop and orchard configurations. Engine options included gasoline, diesel and LP-gas, all sharing the same basic Waukesha-Oliver 3.5L six-cylinder engine.
This generally handy tractor tested at 44 horsepower at the drawbar and claims 47 horsepower for the PTO. Standard options included the three-point hitch and PTO. Power steering is also available but hard to find.
One of the big upgrades offered in the Oliver 770 was the Power Booster system. This system was similar to International Harvester’s Torque Amplifier, except the Power Booster system was fully mechanical. (Other brands, in contrast, commonly had hydraulically actuated systems.)
The Power Booster system was a great innovation in its day but, compared to later refinements, it can be difficult to operate and repair. Midway through the production line, Oliver replaced the Power Booster system with the superior HydroPower system. Most tractors that originally came with a Power Booster were later changed over to a HydroPower.
While the Power Booster leaves much to be desired, the HydroPower system is fantastic. The entire system is oil bathed, just like an automatic transmission in a modern car. Compared to other torque-amplifier systems that leave some parts dry, the HydroPower’s design cuts down on friction and the resulting heat in the drive components. This system makes the tractor particularly smooth to operate and long-lasting.