Challenger 65E, Challenger 75E, Challenger 85E and Challenger 95E Agricultural Tractors Power Train Caterpillar

Introduction

The transmission is a direct drive power shift transmission that has ten forward gears and two reverse gears. Six of the forward gears are closely spaced in the normal work range of 6.5 to 12.9 km/h (4 to 8 mph).

The transmission provides a slow gear of 4.2 km/h (2.6 mph) for the Challenger 65E Agricultural Tractors. The transmission provides a slow gear of 4.5 km/h (2.8 mph) for the Challenger 75E, Challenger 85E and Challenger 95E Agricultural Tractors. A roading gear of 29.1 km/h (18 mph) is provided for all four machines.

The transmission is a "countershaft/planetary" transmission with four rotating clutches in the countershaft portion of the transmission. The four rotating clutches are No. 1 clutch, No. 2 clutch, No. 7 clutch and No. 8 clutch. The transmission has a planetary system with four clutches on the output shaft centerline. The clutches are No. 3 clutch, No. 4 clutch, No. 5 clutch and No. 6 clutch.

Illustration 1	g00558254
Clutch operation (Typical example) (A) Piston (B) Spring (C) Plates (D) Housing (clutch) (E) Discs (F) Gear (ring)

The eight transmission clutches are of the disc type. Each clutch has discs (E) and plates (C). The inside teeth of discs (E) are engaged with the outside teeth of ring gear (F). Notches on the outside diameter of plates (C) are engaged with pins in the clutch housing. The pins keep the plates from rotating.

In Illustration 1, springs (B) are between clutch housing (D) and piston (A). The springs keep the clutches disengaged. The clutches are engaged when oil is sent into the area behind piston (A). When the pressure of the oil in the area behind the piston increases, the piston moves to the right. When the pressure of the oil in the area behind the piston increases, the piston will push the discs and the plates together against the force of spring (B). The clutch is now engaged. The discs keep ring gear (6) from rotating. When the clutch is released, the pressure in the area behind piston (A) decreases and the force of spring (B) moves the piston to the left. The discs and plates are now separated. The clutch is not engaged.

Illustration 2	g00558259
Oil Level Sight Gauge for the Transmission

The transmission oil level should be checked daily. The oil level can be checked from the outside of the tractor. Look between the front idler and the suspension on the left side of the tractor. Refer to Operation and Maintenance Manual, SEBU7072 for additional information.

Transmission Components

Note: The following illustrations are of the Challenger 65E transmission. Challenger 75E, Challenger 85E and Challenger 95E Agricultural Tractors have the same operation and power flow of the transmission as Challenger 65E Agricultural Tractors with only minor differences. Refer to Specifications, SENR1733 for additional information about the differences.

Illustration 3	g00558263
Transmission components (1) Input shaft (2) Gear (3) No. 2 clutch (4) Gear (part of shaft assembly (8) ) (5) No. 1 clutch (6) Gear (7) Gear (8) Shaft assembly (upper countershaft) (9) Gear (10) No. 3 carrier (11) No. 3 sun gear (12) No. 3 planetary gears (13) No. 3 ring gear (14) No. 4 sun gear (15) No. 4 carrier (16) No. 4 planetary gears (17) No. 4 ring gear (18) No. 5 carrier (19) No. 5 sun gear (20) No. 5 planetary gears (21) No. 5 ring gear (22) No. 6 planetary gears (23) Reverse idler gear (24) Gear (25) Gear assembly (lower countershaft) (26) No. 3 clutch (27) No. 4 clutch (28) No. 5 clutch (29) No. 6 clutch (30) No. 6 ring gear (31) No. 6 sun gear (32) No. 6 carrier (33) Shaft (34) Planetary input shaft (35) No. 7 clutch (36) Gear (part of gear assembly (25) ) (37) No. 8 clutch

The countershaft portion of the transmission drives the implement pump, the differential steering pump and the transmission pump. A power take-off (PTO) can be mounted on the countershaft portion of the transmission. The power take-off is offered as an attachment. The PTO is driven by input shaft (1).

Illustration 4	g00558329
Pump drive (38) Pump drive shaft (39) Gear

The large gear that is part of gear (7) drives gear (39) that is on pump drive shaft (38). The implement pump and the differential steering pump is driven by pump drive shaft (38).

Illustration 5	g00558336
Pump drive (23) Reverse idler gear and transmission pump drive gear (40) Pump drive shaft

Gear (9) drives reverse idler gear (23). Reverse idler gear (23) drives pump drive shaft (40) which drives the transmission pump. Reverse idler gear (23) drives gear (24). When No. 8 reverse clutch is engaged, this gives the reverse rotation for the reverse gears.

A countershaft clutch and a planetary clutch must be engaged in order to send power through the transmission. This will rotate the planetary clutches as a unit. There is one exception. The planetary clutches will rotate as a unit in the ninth gear or the tenth gear when the No. 7 clutch is engaged.

Note: The following table gives the combination of the clutches that are engaged for each FORWARD and REVERSE positions.

Illustration 6	g00558341
Locations of Transmission Shaft (front view of the transmission case) (1) Input shaft (8) Shaft assembly (upper countershaft) (25) Gear assembly (lower countershaft) (34) Planetary input shaft (shaft behind gear assembly (25) ) (38) Pump drive shaft (40) Reverse idler and transmission pump drive

Neutral

Illustration 7	g00558547
Power flow (Neutral) (1) Input shaft (2) Gear (6) Gear (7) Gear (8) Shaft assembly (upper countershaft) (9) Gear (23) Reverse idler gear (24) Gear (25) Gear assembly (lower countershaft) (35) No. 7 clutch

When the transmission is in the NEUTRAL position, only No. 7 clutch (35) is engaged.

Torque from the engine is transferred to input shaft (1). Gears (2) and (6) are splined to input shaft (1). Gears (2) and (6) turn gears (7) and (9). Gears (7) and (9) turn on the bearings. Gears (7) and (9) are not connected to shaft assembly (8). Because No. 1 or No. 2 clutch is not engaged, there is no transfer of torque to shaft assembly (8) and to the planetary assembly.

Gear (9) is in engagement with reverse idler gear (23). This causes reverse idler gear (23) to turn. Reverse idler gear (23) then turns gear (24). Because No. 8 clutch is not engaged, there is no torque transfer to gear assembly (25) and the planetary assembly.

Because torque from the engine never reaches No. 7 clutch or the planetary assembly, there is no power flow to the output yoke.

First Gear (Forward)

Illustration 8	g00604334
Power flow (First gear (Forward)) (1) Input shaft (2) Gear (4) Gear (part of shaft assembly (8) ) (5) No. 1 clutch (6) Gear (7) Gear (8) Shaft assembly (upper countershaft) (9) Gear (10) No. 3 carrier (11) No. 3 sun gear (12) No. 3 planetary gears (13) No. 3 ring gear (25) Gear assembly (lower countershaft) (26) No. 3 clutch (34) Planetary input shaft (36) Gear (part of gear assembly (25) )

When the transmission is in first gear (forward), No. 1 clutch (5) and No. 3 clutch (26) are engaged. The No. 3 clutch holds ring gear (13) for the No. 3 clutch stationary. The No. 1 clutch (5) connects gear (9) with shaft assembly (8) .

Torque from the engine is transferred to input shaft (1). Gears (2) and (6) are splined to input shaft (1). Gears (2) and (6) turn gears (7) and (9). Gears (7) and (9) turn on the bearings. Gears (7) and (9) are not connected to shaft assembly (8) .

Gear (9) is connected by splines to the hub for No. 1 clutch (5). When the No. 1 clutch is engaged, torque is transferred through the engaged No. 1 clutch (5) to gear (4). Gear (4) is part of shaft assembly (8). Gear (4) turns gear (36). Gear (36) is part of gear assembly (25) .

Planetary input shaft (34) is splined to gear assembly (25). Gear assembly (25) turns planetary input shaft (34) in the same direction as input shaft (1). Planetary input shaft (34) turns No. 3 sun gear (11) .

No. 3 sun gear (11) turns No. 3 planetary gears (12). Because No. 3 ring gear (13) is held stationary by the engaged No. 3 clutch (26), planetary gears (12) move around the inside of the ring gear. The movement of the No. 3 planetary gears causes No. 3 carrier (10) to turn. No. 3 carrier turns the output yoke.

Second Gear (Forward)

Illustration 9	g00584764
Power flow (Second gear (Forward)) (1) Input shaft (2) Gear (3) No. 2 clutch (4) Gear (part of shaft assembly (8) ) (6) Gear (7) Gear (8) Shaft assembly (upper countershaft) (9) Gear (10) No. 3 carrier (11) No. 3 sun gear (12) No. 3 planetary gears (13) No. 3 ring gear (25) Gear assembly (lower countershaft) (26) No. 3 clutch (34) Planetary input shaft (36) Gear (part of gear assembly (25) )

When the transmission is in second gear (forward), No. 2 clutch (3) and No. 3 clutch (26) are engaged. The No. 3 clutch holds ring gear (13) for the No. 3 clutch stationary. The No. 2 clutch (3) connects gear (7) with shaft assembly (8) .

Torque from the engine is transferred to input shaft (1). Gears (2) and (6) are splined to input shaft (1). Gears (2) and (6) turn gears (7) and (9). Gears (7) and (9) turn on the bearings. Gears (7) and (9) are not connected to shaft assembly (8) .

Gear (7) is connected by splines to the hub for No. 2 clutch (3). When the No. 2 clutch is engaged, torque is transferred through the engaged No. 2 clutch (3) to gear (4). Gear (4) is part of shaft assembly (8). Gear (4) turns gear (36). Gear (36) is part of shaft assembly (25). Planetary input shaft (34) is splined to gear assembly (25) .

Gear assembly (25) turns planetary input shaft (34) in the same direction as input shaft (1). Planetary input shaft (34) turns No. 3 sun gear (11). No. 3 sun gear (11) turns No. 3 planetary gears (12) .

Because No. 3 ring gear is held stationary by the engaged No. 3 clutch, planetary gears (12) move around the inside of the ring gear. The movement of the No. 3 planetary gears causes No. 3 carrier (10) to turn. No. 3 carrier turns the output yoke.

Third Gear (Forward)

Illustration 10	g00584772
Power flow (Third gear (Forward)) (1) Input shaft (2) Gear (4) Gear (part of shaft assembly (8) ) (5) No. 1 clutch (6) Gear (7) Gear (8) Shaft assembly (upper countershaft) (9) Gear (10) No. 3 carrier (11) No. 3 sun gear (12) No. 3 planetary gears (13) No. 3 ring gear (14) No. 4 sun gear (15) No. 4 carrier (16) No. 4 planetary gears (17) No. 4 ring gear (25) Gear assembly (lower countershaft) (27) No. 4 clutch (34) Planetary input shaft (36) Gear (part of gear assembly (25) )

When the transmission is in third gear (forward), No. 1 clutch (5) and No. 4 clutch (27) are engaged. The No. 4 clutch holds ring gear (17) for the No. 4 clutch stationary. The No. 1 clutch (5) connects gear (9) with shaft assembly (8) .

Torque from the engine is transferred to input shaft (1). Gears (2) and (6) are splined to input shaft (1). Gears (2) and (6) turn gear (7) and (9). Gears (7) and (9) turn on the bearings. Gears (7) and (9) are not connected to shaft assembly (8) .

Gear (9) is connected by splines to the hub for No. 1 clutch (5). When the No. 1 clutch is engaged, torque is transferred through the engaged No. 1 clutch (5) to gear (4). Gear (4) is part of shaft assembly (8) .

Gear (4) turns gear (36). Gear (36) is part of gear assembly (25). Planetary input shaft (34) is splined to gear assembly (25). Gear assembly (25) turns planetary input shaft (34) in the same direction as input shaft (1) .

No. 3 sun gear (11) and No. 4 sun gear (14) are splined to planetary input shaft (34). No. 3 sun gear (11) and No. 4 sun gear (14) turn with planetary input shaft (34). No. 4 sun gear (14) turns No. 4 planetary gears (16). Because No. 4 ring gear (17) is held stationary by the engaged No. 4 clutch, No. 4 planetary gears (16) move around the inside of the ring gear. The movement of the No. 4 planetary gears cause No. 4 carrier (15) to turn.

No. 3 ring gear (13) is splined to No. 4 carrier (15). No. 3 ring gear (13) turns No. 4 carrier (15). No. 3 planetary gears (12) are being driven by No. 3 sun gear (11) and No. 3 ring gear (13). No. 3 sun gear (11) and No. 3 ring gear (13) are turning in the same direction, but at different speeds. The movement of No. 3 planetary gears (12) causes No. 3 carrier (10) to turn. No. 3 carrier turns the output yoke.

Fourth Gear (Forward)

Illustration 11	g00584775
Power flow (Third gear (Forward)) (1) Input shaft (2) Gear (3) No. 2 clutch (4) Gear (part of shaft assembly (8) ) (5) No. 1 clutch (6) Gear (7) Gear (8) Shaft assembly (upper countershaft) (9) Gear (10) No. 3 carrier (11) No. 3 sun gear (12) No. 3 planetary gears (13) No. 3 ring gear (14) No. 4 sun gear (15) No. 4 carrier (16) No. 4 planetary gears (17) No. 4 ring gear (18) No. 5 carrier (19) No. 5 sun gear (20) No. 5 planetary gears (21) No. 5 ring gear (25) Gear assembly (lower countershaft) (28) No. 5 clutch (33) Shaft (34) Planetary input shaft (36) Gear (part of gear assembly (25) )

When the transmission is in fourth gear (forward), No. 1 clutch (5) and No. 5 clutch (28) are engaged. The No. 5 clutch holds ring gear (21) for the No. 5 clutch stationary. The No. 1 clutch (5) connects gear (7) with shaft assembly (8) .

Torque from the engine is transferred to input shaft (1). Gears (2) and (6) are splined to input shaft (1). Gears (2) and (6) turn gears (7) and (9). Gears (7) and (9) turn on the bearings. Gears (7) and (9) are not connected to shaft assembly (8) .

Gear (9) is connected by splines to the hub for No. 2 clutch (3). When the No. 1 clutch is engaged, torque is transferred through the engaged No. 1 clutch (5) to gear (4). Gear (4) is part of shaft assembly (8) .

Gear (4) turns gear (36). Gear (36) is part of gear assembly (25). Planetary input shaft (34) is splined to gear assembly (25). Gear assembly (25) turns planetary input shaft (34) .

No. 3 sun gear (11) and No. 4 sun gear (14) are splined to planetary input shaft (34). No. 3 sun gear (11) and No. 4 sun gear (14) turn with planetary input shaft (34). No. 4 sun gear (14) turns No. 4 planetary gears (16) and No. 4 carrier (15). No. 4 carrier (15) is splined to shaft (33) .

Shaft (33) turns No. 5 sun gear (19). No. 5 sun gear turns No. 5 planetary gears. Because No. 5 ring gear (21) is held stationary by the engaged No. 5 planetary gears (20) move around the inside of the ring gear. The movement of the No. 5 planetary gears causes No. 5 carrier (18) to turn.

No. 4 ring gear (17) is splined to No. 5 carrier (18). No. 4 ring gear (17) turns with No. 5 carrier (18). No. 4 planetary gears (16) are being driven by No. 4 sun gear (14) and No. 4 ring gear (17). No. 4 sun gear (14) and No. 4 ring gear (17) turn in the same direction, but at different speeds. The movement of No. 4 planetary gears causes No. 4 carrier (18) to turn.

No. 3 ring gear (13) is splined to No. 4 carrier (15). No. 3 ring gear (13) turns No. 4 carrier (15). No. 3 planetary gears (12) are being driven by No. 3 sun gear (11) and No. 3 ring gear (13). No. 3 sun gear (11) and No. 3 ring gear (13) are turning in the same direction, but at different speeds. The movement of No. 3 planetary gears (12) causes No. 3 carrier (10) to turn. No. 3 carrier turns the output yoke.

Fifth Gear (Forward)

Illustration 12	g00559013
Power Flow (Fifth gear (Forward)) (1) Input shaft (2) Gear (4) Gear (part of shaft assembly (8) ) (5) No. 1 clutch (6) Gear (7) Gear (8) Shaft assembly (upper countershaft) (9) Gear (10) No. 3 carrier (11) No. 3 sun gear (12) No. 3 planetary gears (13) No. 3 ring gear (14) No. 4 sun gear (15) No. 4 carrier (16) No. 4 planetary gears (17) No. 4 ring gear (18) No. 5 carrier (19) No. 5 sun gear (20) No. 5 planetary gears (21) No. 5 ring gear (22) No. 6 planetary gears (25) Gear assembly (lower countershaft) (29) No. 6 clutch (30) No. 6 ring gear (31) No. 6 sun gear (32) No. 6 carrier (33) Shaft (34) Planetary input shaft (36) Gear (part of gear assembly (25) )

When the transmission is in fifth gear (forward), No. 1 clutch (5) and No. 6 clutch (29) are engaged. The No. 6 clutch holds ring gear (30) for the No. 6 clutch stationary. The No. 1 clutch (5) connects gear (7) with shaft assembly (8) .

Torque from the engine is transferred to input shaft (1). Gears (2) and (6) are splined to input shaft (1). Gears (2) and (6) turn gears (7) and (9). Gears (7) and (9) turn on the bearings. Gears (7) and (9) are not connected to shaft assembly (8) .

Gear (9) is connected by splines to the hub for No. 1 clutch (5). When the No. 1 clutch is engaged, torque is transferred through the engaged No. 1 clutch (5) to gear (4). Gear (4) is part of shaft assembly (8). Gear (4) turns gear (36). Gear (36) is part of gear assembly (25). Planetary input shaft (34) is splined to gear assembly (25). Gear assembly (25) turns planetary input shaft (34) .

No. 3 sun gear (11) and No. 4 sun gear (14) are splined to planetary input shaft (34). No. 3 sun gear (11) and No. 4 sun gear (14) turn with planetary input shaft (34). No. 4 sun gear (14) turns No. 4 planetary gears (16) and No. 4 carrier (15). No. 4 carrier (15) is splined to shaft (33) .

Shaft (33) turns No. 5 sun gear (19) and No. 6 sun gear (31). The No. 6 sun gear (31) turns No. 6 planetary gears (22). Because No. 6 ring gear (30) is held stationary by engaged No. 6 clutch (29), planetary gears (22) move around the inside of ring gear (30). The movement of No. 6 planetary gears causes No. 6 carrier (32) to turn.

No. 5 ring gear (21) is splined to No. 6 carrier (32). No. 5 ring gear (21) turns with No. 6 carrier (32). No. 5 planetary gears (20) are being driven by No. 5 sun gear (19) and No. 5 ring gear (21). No. 5 sun gear (19) and No. 5 ring gear (21) turn in the same direction, but at different speeds. The movement of No. 5 planetary gears causes No. 5 carrier (18) to turn.

No. 4 ring gear (17) is splined to No. 5 carrier (18). No. 4 ring gear (17) turns with No. 5 carrier (18). No. 4 planetary gears (16) are being driven by No. 4 sun gear (14) and No. 4 ring gear (17). No. 4 sun gear (14) and No. 4 ring gear (17) turn in the same direction, but at different speeds. The movement of No. 4 planetary gears causes No. 4 carrier (15) to turn.

No. 3 ring gear (13) is splined to No. 4 carrier (15). No. 3 ring gear (13) turns with No. 4 carrier (15). No. 3 planetary gears (12) are being driven by No. 3 sun gear (11) and No. 3 ring gear (13). No. 3 sun gear (11) and No. 3 ring gear (13) turn in the same direction, but at different speeds. The movement of No. 3 planetary gears (12) causes No. 3 carrier (10) to turn. No. 3 carrier turns the output yoke.

Sixth Gear, Seventh Gear, and Eighth Gear (Forward)

The sixth gear (forward), the seventh gear (forward), and the eighth gear (forward) have the same power flow as the third gear (forward), fourth gear (forward), and fifth gear (forward). There is one exception. The No. 2 countershaft clutch is engaged instead of the No. 1 countershaft clutch.

See the "Second Gear FORWARD" topic for additional information. This topic describes the power flow of the countershaft portion of the transmission when No. 2 clutch is engaged.

Ninth Gear (Forward)

Illustration 13	g00559075
Power flow (Ninth gear (Forward)) (1) Input shaft (2) Gear (3) No. 2 clutch (4) Gear (part of shaft assembly (8) ) (5) No. 1 clutch (6) Gear (7) Gear (8) Shaft assembly (upper countershaft) (9) Gear (10) No. 3 carrier (11) No. 3 sun gear (13) No. 3 ring gear (15) No. 4 carrier (25) Gear assembly (lower countershaft) (33) Shaft (34) Planetary input shaft (35) No. 7 clutch (36) Gear (part of gear assembly (25) )

When the transmission is in ninth gear (forward), No. 1 clutch (5) and No. 7 clutch (35) are engaged. No. 1 clutch (5) connects gear (4) with shaft assembly (8). No. 7 clutch (35) connects gear assembly (25) with shaft (33) .

Torque from the engine is transferred to input shaft (1). Gears (2) and (6) are splined to input shaft (1). Gears (2) and (6) turn gears (7) and (9). Gears (7) and (9) turn on the bearings. Gears (7) and (9) are not connected to shaft assembly (8) .

Gear (9) is connected by splines to the hub for No. 1 clutch (5). When the No. 1 clutch is engaged, torque is transferred through the engaged No. 1 clutch (5) to gear (4). Gear (4) is part of shaft assembly (8) .

Gear (4) turns gear (36). Gear (36) is part of gear assembly (25). Planetary input shaft (34) is splined to gear assembly (25). Gear assembly (25) turns planetary input shaft (34). Planetary input shaft (34) turns No. 3 sun gear (11) .

When No. 7 clutch (35) is engaged, torque is transferred from gear assembly (25) through the engaged No. 7 clutch to shaft (33) which causes shaft (33) to turn. No. 4 carrier (15) is splined to shaft (33). No. 4 carrier (15) turns with shaft (33). No. 3 ring gear (13) is splined to No. 4 carrier (15) and shaft (33). No. 3 ring gear (13) turns with No. 4 carrier (15) and shaft (33) .

When both No. 3 sun gear (11) and No. 3 ring gear (13) are turning in the same direction and the same speed, No. 3 carrier (10) is being held. No. 3 carrier (10) turns also. No. 3 carrier turns the output yoke.

Tenth Gear (Forward)

The No. 2 countershaft clutch is engaged when the transmission is in tenth gear (forward) instead of the No. 1 countershaft clutch. The No. 1 countershaft clutch is engaged in ninth gear (forward). The No. 2 countershaft clutch connects gear (7) with shaft assembly (8). After the power flow leaves the No. 2 countershaft clutch, the flow is identical to the flow in ninth gear (forward).

First Gear (Reverse)

Illustration 14	g00615105
Power flow (First gear (Reverse)) (1) Input shaft (6) Gear (8) Shaft assembly (9) Gear (10) No. 3 carrier (11) No. 3 sun gear (12) No. 3 planetary gears (13) No. 3 ring gear (23) Reverse idler gear (24) Gear (25) Gear assembly (26) No. 3 clutch (34) Planetary input shaft (37) No. 8 clutch

When the transmission is in first gear (reverse), No. 3 clutch (26) and No. 8 clutch (37) are engaged. No. 3 clutch (26) holds ring gear (13) stationary for No. 3 clutch (26). No. 8 clutch (37) connects gear (24) with gear assembly (25) .

Torque from the engine is transferred to input shaft (1). Gear (6) is splined to input shaft (1). Gear (6) turns gear (9). Gear (9) turns on the bearings. Gear (9) is not connected to shaft assembly (8) .

Gear (9) turns reverse idler gear (23). Reverse idler gear (23) is part of the transmission pump drive. Reverse idler gear (23) turns gear (24) in the opposite direction of input shaft (1). Gear (24) is splined to the hub for No. 8 clutch (37) .

Note: From this point, all planetary rotation is the opposite of the rotation in the forward gears.

When No. 8 clutch (37) is engaged, torque is transferred through engaged No. 8 clutch (37) to gear assembly (25). Planetary input shaft (34) is splined to gear assembly (25). Gear assembly (25) turns planetary input shaft (34) .

Planetary input shaft (34) turns No. 3 sun gear (11). No. 3 sun gear (11) turns No. 3 planetary gear (12). Since No. 3 ring gear (13) is held stationary by engaged No. 3 clutch (26), No. 3 planetary gears (12) move around the inside of No. 3 ring gear (13). The movement of No. 3 planetary gears (13) causes No. 3 carrier (10) to turn. No. 3 carrier (10) turns the output yoke.

Second Gear (Reverse)

Second gear (reverse) has an identical power flow in comparison to first gear (reverse) with one exception. The No. 6 planetary clutch is engaged instead of the No. 3 planetary clutch. The "Fifth Gear (Forward)" story describes the power flow in the planetary system. The No. 6 clutch is engaged in this description. The power flow is identical except that all the rotations are reversed.