Diagram and Real Location of Power Shift Transmission Caterpillar D9R

The D9R transmission is located at the rear of the machine for easy removal and installation. The three-speed forward, three-speed reverse planetary power shift transmission transfers power from the engine to the final drives. The transmission contains three hydraulically controlled speed clutches and two hydraulically controlled directional clutches. The operator manually selects the direction and speed range. With a transmission speed and directional clutch ENGAGED, the transmission sends power to the pinion and bevel gear, the steering clutches and brakes (non-differential steer machines), and the final drives. Differential steer machines are equipped with an additional drive input and planetary gear set for steering which replace the steering clutches.

power shift compponent location

The speed clutch pressure (P1) test port (1), and the directional clutch pressure (P2) test port (2) are located on the rear of the transmission housing. The plugs are removed and replaced with test fittings to measure the P1 and P2 pressures. The torque converter inlet pressure tap (3) and the transmission lube pressure tap (4) are also located on the rear of the transmission housing.

power shift compponent location 2

Shown here is a sectional view of the transmission group. The planetary group has two directional and three speed clutches which are numbered in sequence (1 through 5) from the rear of the transmission to the front.

Clutches No. 1 and 2 are the reverse and forward directional clutches. Clutches No. 3, 4, and 5 are the third, second, and first speed clutches. The No. 5 clutch is a rotating clutch.

In this sectional view of the transmission, the input shaft and input sun gears are shown in red. The output shaft and output sun gears are blue. The ring gears are shown in green. The planetary carriers are brown. The planet gears and shafts are shown in orange. The clutch discs, clutch plates, pistons, springs, and bearings are shown in yellow. The stationary clutch housings are shown in gray.

The input sun gears are splined to the input shaft and drive the directional gear trains. The output shaft is driven by sun gears No. 3 and 4 and rotating clutch No. 5. When the No. 2, 3, or 4 clutches are engaged, their respective ring gears are held stationary. The No. 1 planetary carrier is held when the No. 1 clutch is engaged. When engaged, the No. 5 rotating clutch locks the output components (for FIRST gear) to the output shaft.

power shift compponent location 3

The power train oil dipstick (1) and fill tube (2) are located below a hinged cover on the left side of the machine. Also located in this compartment are the machine disconnect switch (3) and the oil fill cap (4) for the pivot shaft compartment.

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