WhichTractor
  • WhichTractor size: Standard-size
  • No lab test on file
  • 1972–1976
  • 9,367 built

WhichTractor size, not the maker’s category

International Harvester 666 Transmission specs

11 transmission values on record for the 666.

Engine power, claimed · gross or net not stated

66.1 hp

49.3 kW as stated by the source

No lab test on file

Claimed · standard not stated by the source

Source · Traktorenlexikon, “IHC 666”, claimed

This is the maker’s own figure, measured at the engine. Power at the PTO is lower — by how much, for this machine, nobody has measured.

How fast will a 666 go?

The fastest speed on record for a 666 is 18.6 mph (30 km/h). The gearbox itself is not on record yet.

Transmission — 666 Transmission
Drive2WDSource 1
Forward gears5–10the article lists alternatives
Reverse gears1–2Source 1the article lists alternatives
Transmission as described5 forward/1 reverse, 10 forward/2 reverse and stepless
Stepless transmissionCVTSource 1
ClutchPedal-operated dry single-plate clutchSource 1
Top speed forward18.6 mph · 30 km/h
Top speed reverse9.7 mph · 15.69 km/hhighest reverse speed printed in the article's speed tables
Service brakesHydraulically operated disc brakes acting on differential side shaftsSources disagreeHydraulically operated disc brakes acting on the differential side shafts (Traktorenlexikon, “Farmall Farmall 666”)
Differential lockMechanically operated differential lockSource 1
Front axleOscillating, extendable front axle

Source · Traktorenlexikon, “IHC 666”

Sources and how this page was built

11 transmission values from Traktorenlexikon, “IHC 666”; and Traktorenlexikon, “Farmall Farmall 666”.

Sources checked

14 SEP 2026

Spotted an error?

Sources

Facts taken from these documents, units converted. Numbers beside a figure refer to this list. Licences and attribution

  1. Traktorenlexikon: Farmall Farmall 666 — CC BY-SA 4.0, WIKIBOOKS-TL-118860 · revision 1034709. Wikibooks contributors (Traktorenlexikon). Original document
  2. Traktorenlexikon: IHC 666 — CC BY-SA 4.0, WIKIBOOKS-TL-118859 · revision 1034710. Wikibooks contributors (Traktorenlexikon). Original document