Page 35 - Hydra-matic 6 Speed RWD Technician's Guide (October 2005)

PLANETARY GEARSETS

OUTPUT PLANETARY GEARSET COMPONENTS

OUTPUT
CARRIER
INTERNAL
OUTPUT OUTPUT FRONT
CARRIER CARRIER GEAR
FRONT SUN ASSEMBLY (495)
GEAR (68)
(487)

INPUT
CARRIER
ASSEMBLY
(52) INPUT
INTERNAL 4-5-6 OUTPUT
GEAR CARRIER OUTPUT
(w/ TURBINE SHAFT)
CLUTCH REAR SUN CARRIER
INPUT ASSEMBLY GEAR INTERNAL
SUN GEAR (56) (489) REAR
(53) GEAR
(497)

INPUT PLANETARY GEARSET COMPONENTS

Figure 26
REDUCTION:
Increasing the output torque is known as operating in reduction gether through differential speed connections to achieve the correct
because there is a decrease in the speed of the output member 4th or 5th gear ratio.
proportional to the increase in the output torque. Therefore, with a In 6th gear, powerflow does not travel through the input planetary
constant input speed, the output torque increases when the gearset. Powerflow travels through the output planetary gearset,
transmission is in a lower gear, or higher gear ratio. Reduction where the output carrier is driving, the front output sun gear is held
occurs in 1st through 4th gears and Reverse. Each of these ranges and the output carrier pinion gears walk around the stationary sun
use the input planetary gearset for an initial reduction step before gear and drive the output front internal gear in a ratio of 0.667:1.
powerflow continues to the output planetary gearset, where the
final output ratio is achieved. REVERSE:
A planetary gearset reverses the direction of powerflow rotation
The input planetary gearset functions the same in each range. The when the carrier assembly is held stationary and power is applied
input internal gear, which is splined and staked into the 4-5-6 (w/ to the sun gear. This causes the pinion gears to act as idler gears
turbine shaft) clutch assembly (56), is driving, the input sun gear and drive the internal gear in the opposite direction.
(53) is held (splined to the pump hub), and the input carrier (52) is
driven. The input carrier is splined to the 1-2-3-4 and 3-5 reverse Once again, powerflow travels through the input planetary carrier
clutch assembly (51), which is turning in reduction from the input for an initial reduction of 1.532:1, then continues to the output
carrier pinions walking around the stationary sun gear. carrier. The output front sun gear is driving, the output carrier is
held stationary, and the pinion gears are forced to walk around the
OVERDRIVE: stationary sun gear. The pinion gears drive the output front internal
Overdrive enables the output speed of the transmission to be greater gear in the opposite direction of engine rotation. Reverse has a
than the input speed. This mode of operation allows the vehicle to ratio reduction of 3.064:1.
maintain a given road speed with reduced engine speed to improve Gear ratios are based on the 6L80 application. See page 11 for
fuel economy. In Overdrive, the output speed increases while the the complete list of ratios.
output torque decreases proportionally. Overdrive occurs in 5th Refer to the powerflow section on page 49 for a complete
and 6th gears.
description of clutch combinations used to hold and/or drive the
In 4th and 5th gears powerflow travels through the input gearset, and planetary gearsets for each gear range.
continues to the output gearset. Without a member of the output Gearset failure can cause noise and loss of drive.
gearset being held (grounded), the two planetary gearsets act to-
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