Komatsu GD555-5 Operation & Maintenance Manual page 165

OPERATION
When going downhill, shift down the transmission to use the engine brake.
To prevent the engine from overrunning, the rotation range enabling downshifts is limited. Reduce the travel speed by
depressing the brake pedal and, after the speed becomes within the range where downshifts are possible, carry out the
downshift operation.
Gear speed
F2 -> F1
F3 -> F2
F4 -> F3
F5 -> F4
F6 -> F5
F7 -> F6
F8 -> F7
3 - 112
Travel speed enabling
downshifts (km/h, (MPH))
4.5 (2.8)
6.5 (4.0)
9.0 (5.6)
13.0 (8.1)
20.0 (12.4)
29.0 (18.0)
39.5 (24.5)
WARNING
OPERATION