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Home >> Land Rover >> 2021 >> Defender 110 >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Automatic Transmission -- Defender/L663 >> Automatic Transmission (G2391363) >> Description And Operation >> Transmission Description - Vehicles With: 8HP76 8-Speed Automatic Transmission, AWD (G2391364) >> Operation >> Power Flows

Power Flows

Operation of the transmission is controlled by the TCM  , which electrically activates various solenoids to control the transmission gear selection.

All gear shifts from 1st to 8th and 8th to 1st are known as 'overlap' shifts. Overlap shifts are during a gear shift 1 clutch must remain capable of transmitting torque at a reduced main pressure until the other clutch is ready to accept the torque.

G11599673Courtesy of JAGUAR LAND ROVER NORTH AMERICA, LLC
ITEM DESCRIPTION
A Multiplate brake
B Multiplate brake
C Multiplate brake
D Multiplate brake
E Multiplate brake
1 Ring gear of planetary gear set 1
2 Planetary gears of planetary gear set 1
3 Sun gear of planetary gear set 1
4 Ring gear of planetary gear set 2
5 Planetary gears of planetary gear set 2
6 Sun gear of planetary gear set 2
7 Ring gear of planetary gear set 3
8 Planetary gears of planetary gear set 3
9 Sun gear of planetary gear set 3
10 Ring gear of planetary gear set 4
11 Planetary gears of planetary gear set 4
12 Sun gear of planetary gear set 4
13 Power input from torque converter
14 Power output to output shaft

Engine torque is transferred, through operation of single or combinations of clutches to the 4 planetary gear trains. All gear trains are controlled by reactionary inputs from brake clutches to produce the 8 forward gears and 1 reverse gear.

GEAR RATIOS SPECIFICATION

GEAR 1ST 2ND 3RD 4TH 5TH 6TH 7TH 8TH REVERSE
Ratio  5.500 3.520 2.200 1.720 1.317 1.000 0.823 0.640 -3.993