Description

Clutches

The four speed automatic transmission uses hydraulically actuated clutches to engage or disengage the transmission gears. When clutch pressure is introduced into the clutch drum, the clutch piston is applied. This presses the friction discs and steel plates together, locking them so they don't slip. Power is then transmitted through the engaged clutch pack to its hub-mounted gear.

Likewise, when clutch pressure is bled from the clutch pack, the piston releases the friction discs and steel plates, and they are free to slide past each other while disengaged. This allows the gear to spin independently of its shaft, transmitting no power.

[1st Clutch]
The first clutch engages/disengages first gear, and is located at the end of the mainshaft, just behind the R side cover. The first clutch is supplied clutch pressure by its oil feed pipe within the mainshaft.

[1st-hold Clutch]
The first hold clutch engages/disengages 1st-hold or 1 position, and is located at the center of the sub-shaft. The 1 sthold clutch is supplied clutch pressure by its oil feed pipe within the sub-shaft.

[2nd Clutch]
The second clutch engages/disengages second gear, and is located at the center of the mainshaft. The second clutch is joined back-to-back to the fourth clutch. The second clutch is supplied clutch pressure through the mainshaft by a circuit connected to the regulator valve body.

[3rd Clutch]
The third clutch engages/disengages third gear, and is located at the end of the countershaft, opposite the R side cover. The third clutch is supplied clutch pressure by its oil feed pipe within the countershaft.

[4th Clutch]
The fourth clutch engages/disengages fourth gear, as well as reverse gear, and is located at the center of the mainshaft. The fourth clutch is joined back-to-back to the second clutch. The fourth clutch is supplied clutch pressure by its oil feed pipe within the mainshaft.

[One-way Clutch]
The one-way clutch is positioned between the parking gear and first gear, with the parking gear splined to the countershaft. The first gear provides the outer race surface, and the parking gear provides the inner race surface. The one-way clutch locks up when power is transmitted from the mainshaft first gear to the countershaft first gear. The first clutch and gears remain engaged in the 1st, 2nd, 3rd, and 4th gear ranges in the I D41, 1 D31 or 2 position. However, the one-way clutch disengages when the 2nd, 3rd, or 4th clutches /gears are applied in the I D4 F, D3 or n position. This is because the increased rotational speed of the gears on the countershaft over-ride the locking "speed range" of the one-way clutch. Thereafter, the one-way clutch free-wheels with the first clutch still engaged.

NOTE: View from R. side cover side.