Manual LO

Manual Lo:

MANUAL LO

CONVERTER CLUTCH - RELEASED
THIRD CLUTCH - APPLIED
THIRD ROLLER CLUTCH - HOLDING
INPUT CLUTCH - APPLIED
INPUT SPRAG - HOLDING
1-2 BAND - APPLIED

When the selector lever is moved to the Manual Lo, D1 position, the manual valve exhausts oil pressure in the PRND432 passage. The manual valve also directs line pressure into the lo passage. Lo oil flows to the following:

Pressure Regulator Valve: Boost line pressure to a steady 1140 kPa (165 psi.) to prevent the clutches from slipping during hard engine braking.

1-2 Shift Valve: At speeds below 40 mph (64 km/h), the 1.2 shift valve closes and directs oil pressure to the following:
a. Second clutch oil exhausts and the second clutch releases.
b. Lo oil fills the Lo-1st passage. Lo-1st oil applies the third clutch.

Throttle Valve (T.V.) Limit Valve: Lo oil forces the T.V. limit valve to open and exhaust T.V. feed oil resulting in no T.V. pressure in Manual Lo.

SUMMARY
The input clutch and sprag drive the input sun gear. The third clutch and third roller clutch provide engine braking by preventing the input sprag from overrunning. The 1-2 band holds the reaction sun gear stationary and line pressure is boosted to prevent the clutches from slipping.