TRUCK SERVICE MANUAL
TRANSMISSION
HT 700D SERIES TRANSMISSIONS
Para 2 -28
Fig. 2-12. Fourth-gear torque path
g. Fourth-Gear Operation (fig. 2-12). Engine
pinions. This rotates the center planetary carrier at a
torque is transmitted through the lockup clutch as
speed reduction. This carrier and the rear planetary
described in b, above. The forward and the third
carrier are splined to the planetary connecting drum.
clutches are applied.
The third-clutch application
The rear carrier hub on the output side is splined to the
anchors the sun gear shaft via the fourth clutch housing,
low ring gear. When the connecting drum rotates, the
against rotation which prevents the integral center sun
rear carrier and the low ring gear rotate at the same
gear from rotating. The forward clutch application locks
speed. This rotation causes the low ring gear to drive
the turbine shaft and main shaft together so they rotate
the low planetary pinions while the low sun gear, which is
as a unit. The rear sun gear is splined to both the main
splined to the rotating main shaft, also drives the low
shaft and the center ring gear and rotates at inputspeed.
pinions. The result is a further change of ratio (from that
With the center sun gear stationary and the center ring
produced in the center planetary). Thus, the output
gear rotating, the ring gear drives the center planetary
shaft, being splined to the rear carrier, rotates at 1.24:1
carrier
reduction.
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