Ford 7840

Ford 6.6L 6-cyl diesel

Bore × stroke

4.4 in × 4.4 in

Rated speed

2,100 rpm

Compression

17.5:1

Cooling

liquid-cooled

Firing order

1-5-3-6-2-4

Notes

6-cylinder 12-valve

EconoShift: Four gears (1-4), plus reverse, in two ranges (L/H). Optional creeper provided a third range. Tractor must be stopped and clutch used to shift gears or range. The eight-speed transmission was only used on the 7840S.

Dual Power: Dual Power adds a two-speed power shift between direct drive and the lower Dual Power range to the basic eight-speed transmission. The Dual Power range is engaged by a switch on the dashboard. Dual Power was an option on the 7840S.

SynchroShift: Four gears (1-4) in three ranges (L/M/H) with right-hand shuttle lever. Gear shifts are synchronized. Shifts between medium and high ranges are synchronized, but the tractor should be stopped to shift to or from low range. Sychronized shuttle shifting. The 12-speed SynchroShift was standard on the 7840 SL. Dual power was an option with the SynchroShift, turning it into a 24-speed transmission.

ElectroShift/Pulse Command: Four power shift gears arranged in two synchronized ratio groups (1-4 and 5-8). Two synchronized ranges (low/high) and right-hand shuttle. Clutch must be used to shift range or move between the lower (1-4) and higher (5-8) gear ratio groups. Push-button power shifting between the four gears in a ratio group. Push-button de-clutching on the shuttle lever allow shifting without the foot clutch. The 16 power shift was standard on the 7840 SLE.