Operation
See the individual topic for each of the system components for a more detailed explanation of the component's function and operation.
Speed Selection (Horsepower Mode)
The Challenger 85E Agricultural Tractor has two electronically controlled horsepower settings. The Challenger 95E Agricultural Tractor has three electronically controlled horsepower settings. The capabilities of the variable horsepower configuration are activated by sensing the transmission output speed.
When first gear (forward) or second gear (forward) is selected, the transmission output speed sensor signals the electronic control module. This will automatically put the engine into the low horsepower mode.
For the Challenger 85E Agricultural Tractor, when third gear (forward) or a higher gear is selected, the high horsepower mode is carried out. The failure of the electronic components within this system will automatically direct the engine into the low horsepower mode. A fault signal will alert the operator that a problem exists.
For the Challenger 95E Agricultural Tractor, when third gear (forward) is selected, a higher horsepower mode is carried out. The engine hp in third gear has been increased to 298 kW (400 hp) for Challenger 95E (PIN: 6KS763-UP) Agricultural Tractors. The engine hp in third gear for Challenger 95E (PIN: 6KS1-762) Agricultural Tractors is 287 kW (385 hp). When fourth gear (forward) or a higher gear is selected, a third horsepower mode is carried out. The failure of the electronic components within this system will automatically direct the engine into the low horsepower mode. A fault signal will alert the operator that a problem exists.
Reference: Refer to Service Manual, RENR1240, "Electronic Troubleshooting 3176C & 3196 Engines" for additional information on troubleshooting the system.
Running Engine in Neutral
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| Illustration 1 | g00577448 |
Transmission Hydraulic Controls (1) Oil cooler bypass valve (2) Oil cooler (3) Lube selector relief valve (4) Relief valve (5) Lube selector spool (6) Lube relief valve (7) Main relief valve (8) Inching lube passage to No. 1 and No. 2 clutches (9) Lube passage to planetary gears and No. 7 and No. 8 clutches (10) Passage to clutch and bearing lube (11) Pump (12) Oil filter (13) Screen assembly in oil sump in transmission case (14) PTO valve (15) Priority valve (16) Rotary actuator group (17) Detent selector spool (18) Priority reduction valve (19) Neutralizer valve (20) Rotary selector spool (21) Selector valve (22) Accumulator (23) Selector piston for No. 3 clutch (24) Load piston for No. 3 clutch (25) Modulation reduction valve for No. 3 clutch (26) Pressure control (27) Modulation reduction valve for No. 8 clutch (28) Load piston for No. 8 clutch (29) Selector piston for No. 8 clutch (30) Selector piston for No. 6 clutch (31) Load piston for No. 6 clutch (32) Modulation reduction valve for No. 6 clutch (33) Modulation reduction valve for No. 2 clutch (34) Load piston for No. 2 clutch (35) Selector piston for No. 2 clutch (36) Selector piston for No. 4 clutch (37) Load piston for No. 4 clutch (38) Modulation reduction valve for No. 4 clutch (39) Modulation reduction valve for No. 7 clutch (40) Load piston for No. 7 clutch (41) Selector piston for No. 7 clutch (42) Selector piston for No. 5 clutch (43) Load piston for No. 5 clutch (44) Modulation reduction valve for No. 5 clutch (45) Modulation reduction valve for No. 1 clutch (46) Load piston for No. 1 clutch (47) Selector piston for No. 1 clutch (48) Manual modulation valve (inching) (49) Manual modulation spool (50) Inching Spool (A) Pressure tap for No. 3 clutch (B) Pressure tap for No. 6 clutch (C) Pressure tap for No. 4 clutch (D) Pressure tap for No. 5 clutch (E) Pressure tap for No. 8 clutch (F) Pressure tap for No. 2 clutch (G) Pressure tap for No. 7 clutch (H) Pressure tap for No. 1 clutch (J) Pressure tap for oil cooler inlet (K) Pressure tap for oil cooler outlet (L) Pressure tap for pump (M) Pressure tap for transmission lubrication (N) Pressure tap for PTO clutch (P) Pressure tap for pilot pressure | |
When the engine is started, oil flows from the oil sump that is in the bottom of the transmission case, through screen assembly (13), pump (11), and oil filter (12) .
From the oil filter, the oil returns to PTO valve (14) (if equipped). As the pressure of the oil increases, priority valve (15) will move down. This allows the oil to flow through internal passages and tubes in the transmission case. The oil will then flow to priority reduction valve (18), rotary actuator (16), and main relief valve (7). Main relief valve (7) is in relief valve (4) .
As the pressure of the oil continues to increase, priority reduction valve (18) moves down. This allows the pump oil to flow to neutralizer valve (19), pressure control (26), and manual modulation valve (48) (inching).
When the pressure in the system reaches 2277 kPa (330 psi), main relief valve (7) moves to the right. The extra oil from main relief valve (7) flows to oil cooler (2). The oil then returns to relief valve (4). This is for lubrication of the transmission clutches and the bearings.
The oil flows through manual modulation valve (48) (inching). This oil comes from the planetary clutch side of pressure control (26). This happens before the oil enters the inching clutch side of the pressure control valve.
When the inching clutch pedal is in the UP (released) position, inching spool (50) and manual modulation spool (49) are all the way to the left.
The pump pressure oil flows to the modulation reduction valves for the inching clutches (No. 1, No. 2, No. 7 and No. 8). The manual modulation valve (inching) also sends pump pressure oil as a signal. This oil is sent to lube selector spool (5) of relief valve (4) .
Lube selector spool (5) moves to the right, permitting full lube flow to the planetary clutches, bearings, and No. 7 and No. 8 clutches through passage (9). No. 1 and No. 2 clutches receive normal lube flow through passage (10) .
If the engine is started with the transmission out of the NEUTRAL position, the position of rotary selector spool (20) will stop the flow of the pump oil to neutralizer valve (19) .
The neutralizer valve does not move down. In this position, neutralizer valve (19) stops the flow of the pilot oil from priority reduction valve (18) to rotary selector spool (20). The clutches in the transmission can not engage.
When rotary selector spool (20) is in the NEUTRAL position, a passage is opened in order to allow the pump oil flow to neutralizer valve (19). The neutralizer valve now moves down. This allows the pilot oil to flow to the rotary selector spool.
The position of rotary selector spool (20) allows the pilot oil to flow to selector piston (41) of pressure control (26). Selector piston (41) and load piston (40) will then move to the left.
The force of the springs causes modulation reduction valve (39) to move to the left. The pump oil will now flow around the modulation reduction valve. The pump oil will also start to fill the No. 7 clutch. The clutch oil also flows through a load piston orifice and flows between selector piston (41) and load piston (40) .
The pressure of the clutch oil increases after the clutch is full of oil. As the pressure of the oil in the No. 7 clutch increases, modulation reduction valve (39) moves to the right and load piston (40) moves to the left.
The load piston orifice in the supply passage to load piston (40) allows the oil flow to the load piston at a specific rate. The pressure in the clutch increases gradually.
The gradual increase in pressure is known as modulation. When the load piston gets all the way to the left against a stop, the modulation stops. The pressure in the No. 7 clutch is now at the maximum pressure. The No. 7 clutch is engaged and the transmission is in neutral.
Neutral to First Gear (Forward)
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| Illustration 2 | g00578084 |
Transmission Hydraulic Controls (1) Oil cooler bypass valve (2) Oil cooler (3) Lube selector relief valve (4) Relief valve (5) Lube selector spool (6) Lube relief valve (7) Main relief valve (8) Inching lube passage to No. 1 and No. 2 clutches (9) Lube passage to planetary gears and No. 7 and No. 8 clutches (10) Passage to clutch and bearing lube (11) Pump (12) Oil filter (13) Screen assembly in oil sump in transmission case (14) PTO valve (15) Priority valve (16) Rotary actuator group (17) Detent selector spool (18) Priority reduction valve (19) Neutralizer valve (20) Rotary selector spool (21) Selector valve (22) Accumulator (23) Selector piston for No. 3 clutch (24) Load piston for No. 3 clutch (25) Modulation reduction valve for No. 3 clutch (26) Pressure control (27) Modulation reduction valve for No. 8 clutch (28) Load piston for No. 8 clutch (29) Selector piston for No. 8 clutch (30) Selector piston for No. 6 clutch (31) Load piston for No. 6 clutch (32) Modulation reduction valve for No. 6 clutch (33) Modulation reduction valve for No. 2 clutch (34) Load piston for No. 2 clutch (35) Selector piston for No. 2 clutch (36) Selector piston for No. 4 clutch (37) Load piston for No. 4 clutch (38) Modulation reduction valve for No. 4 clutch (39) Modulation reduction valve for No. 7 clutch (40) Load piston for No. 7 clutch (41) Selector piston for No. 7 clutch (42) Selector piston for No. 5 clutch (43) Load piston for No. 5 clutch (44) Modulation reduction valve for No. 5 clutch (45) Modulation reduction valve for No. 1 clutch (46) Load piston for No. 1 clutch (47) Selector piston for No. 1 clutch (48) Manual modulation valve (inching) (49) Manual modulation spool (50) Inching Spool (A) Pressure tap for No. 3 clutch (B) Pressure tap for No. 6 clutch (C) Pressure tap for No. 4 clutch (D) Pressure tap for No. 5 clutch (E) Pressure tap for No. 8 clutch (F) Pressure tap for No. 2 clutch (G) Pressure tap for No. 7 clutch (H) Pressure tap for No. 1 clutch (J) Pressure tap for oil cooler inlet (K) Pressure tap for oil cooler outlet (L) Pressure tap for pump (M) Pressure tap for transmission lubrication (N) Pressure tap for PTO clutch (P) Pressure tap for pilot pressure | |
The transmission gear is manually selected by the operator. When the operator moves the transmission gear selector lever, a cable moves detent selector spool (17) into a position for the selected gear.
This opens a chamber in rotary actuator (16). The chamber is then open to a passage to the drain. The pressure oil in the other chamber of rotary actuator (16) moves the vane and the rotor of the rotary actuator until the vane covers the passage to the drain.
The rotor of rotary actuator group (16) is connected to rotary selector spool (20). The movement of the vane and rotor moves the rotary selector spool into position for the selected gear.
The position of the rotary selector spool sends the pilot oil to selector pistons (47) and (23). The position of the rotary selector spool also drains the pilot oil at selector piston (41). Selector piston (41) moves against the load piston body. Selector piston (41) also drains the oil between selector piston (41) and load piston (40). Now, load piston (40) and modulation reduction valve (39) move toward selector piston (41) .
The pump oil to the No. 7 clutch is stopped by modulation reduction valve (39) and the clutch oil in the No. 7 clutch is drained. The No. 7 clutch is released. The pilot oil now moves selector pistons (47) and (23). The No. 1 and No. 3 clutches start to fill.
Modulation takes place between load piston (46) and modulation reduction valve (45) that is for the No. 1 clutch. Modulation also takes place between load piston (24) and modulation reduction valve (25) for the No. 3 clutch.
When the load pistons get all the way against the stops, modulation stops. The pressures in the clutches are at the maximum pressure. The No. 1 and No. 3 clutches are now engaged and the transmission is in first gear (forward).
Manual modulation valve (48) (inching) sends the pump pressure oil to lube selector spool (5) of relief valve (4). This moves lube selector spool (5) to the right. Full lube flow will now enter the planetary clutches, the bearings, the No. 7 clutch, and the No. 8 clutch. This full lube flow comes through passage (9). The No. 1 and No. 2 clutches receive normal lube flow through passage (10) .
The above description is representative of a shift between any gears. There is one exception to the above description. When shifting between two forward gears or shifting between two reverse gears, the two selector pistons and the two clutches are drained.
Inching First Gear (Forward)
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| Illustration 3 | g00578094 |
Transmission Hydraulic Controls (1) Oil cooler bypass valve (2) Oil cooler (3) Lube selector relief valve (4) Relief valve (5) Lube selector spool (6) Lube relief valve (7) Main relief valve (8) Inching lube passage to No. 1 and No. 2 clutches (9) Lube passage to planetary gears and No. 7 and No. 8 clutches (10) Passage to clutch and bearing lube (11) Pump (12) Oil filter (13) Screen assembly in oil sump in transmission case (14) PTO valve (15) Priority valve (16) Rotary actuator group (17) Detent selector spool (18) Priority reduction valve (19) Neutralizer valve (20) Rotary selector spool (21) Selector valve (22) Accumulator (23) Selector piston for No. 3 clutch (24) Load piston for No. 3 clutch (25) Modulation reduction valve for No. 3 clutch (26) Pressure control (27) Modulation reduction valve for No. 8 clutch (28) Load piston for No. 8 clutch (29) Selector piston for No. 8 clutch (30) Selector piston for No. 6 clutch (31) Load piston for No. 6 clutch (32) Modulation reduction valve for No. 6 clutch (33) Modulation reduction valve for No. 2 clutch (34) Load piston for No. 2 clutch (35) Selector piston for No. 2 clutch (36) Selector piston for No. 4 clutch (37) Load piston for No. 4 clutch (38) Modulation reduction valve for No. 4 clutch (39) Modulation reduction valve for No. 7 clutch (40) Load piston for No. 7 clutch (41) Selector piston for No. 7 clutch (42) Selector piston for No. 5 clutch (43) Load piston for No. 5 clutch (44) Modulation reduction valve for No. 5 clutch (45) Modulation reduction valve for No. 1 clutch (46) Load piston for No. 1 clutch (47) Selector piston for No. 1 clutch (48) Manual modulation valve (inching) (49) Manual modulation spool (50) Inching Spool (A) Pressure tap for No. 3 clutch (B) Pressure tap for No. 6 clutch (C) Pressure tap for No. 4 clutch (D) Pressure tap for No. 5 clutch (E) Pressure tap for No. 8 clutch (F) Pressure tap for No. 2 clutch (G) Pressure tap for No. 7 clutch (H) Pressure tap for No. 1 clutch (J) Pressure tap for oil cooler inlet (K) Pressure tap for oil cooler outlet (L) Pressure tap for pump (M) Pressure tap for transmission lubrication (N) Pressure tap for PTO clutch (P) Pressure tap for pilot pressure | |
When the operator depresses the inching clutch pedal to the floor, a cable between the inching clutch pedal and inching spool (50) moves inching spool (50) to the right.
This allows manual modulation spool (49) to move to the right. The flow of pump oil will then be blocked to inching clutches (No. 1, No. 2, No. 7,and No. 8). This will also open the clutches to the drain.
The pressure in the engaged No. 1 clutch rapidly drops to 50 kPa (7 psi) maximum pressure. This causes the No. 1 clutch to disengage. This also causes the signal from manual modulation valve (48) (inching) to relief valve (4) to drop to the same pressure.
Therefore, the signal pressure is not present in order to hold lube selector spool (5) to the right in relief valve (4). Consequently, the force of the spring will move lube selector spool (5) to the left in relief valve (4) .
This opens a chamber and passage (8) to full lubrication flow. This also restricts the flow to the planetary gears and the No. 7 and No. 8 clutches through passage (9). This extra lube oil flow is directed to the slipping clutch by sliders on the clutch shafts. When the clutch piston is moved to begin clutch engagement, the slider moves with the clutch piston. This will open additional passages for oil to flow to the clutch.
When the transmission controls are in the inching mode, lube selector relief valve (3) controls the pressure of the lubrication oil to the inching clutch. The lube selector relief valve (3) also bypasses any excess flow to the planetary lube circuit.
When the operator begins to release the inching clutch pedal, the cable between the inching clutch pedal and inching spool (50) begins to move inching spool (50) to the left.
After a small amount of pedal movement, inching spool (50) has moved manual modulation spool (49) far enough to the left in order to begin to allow pressure oil to the inching clutch side of pressure control (26) and the No. 1 clutch.
The No. 1 clutch begins to engage at a rate that is controlled by the operator. When this pressure reaches 245 kPa (35 psi), manual modulation spool (49) begins to automatically modulate the pressure to full pressure.
The operator no longer has manual control of the inching clutch pressure, even if the operator has not completely released the inching clutch pedal. See Systems Operation/Testing and Adjusting, "Manual Modulation Valve" for additional information of the valve operation.
When the pressure to the inching clutch side of the pressure control reaches approximately 800 kPa (116 psi), the signal to lube selector spool (5) moves the lube selector spool to the right into the position for normal operation.
Reverse Operation
Note: There is no illustration for reverse operation of the machine.
The operation of the transmission hydraulic controls is identical in the reverse and the forward gears. The only exception is for the lube selector spool. When the transmission gear selector lever is moved to a reverse gear, the rotary selector spool sends pilot oil to the selector piston. The selector piston is for the No. 8 clutch (reverse). The rotary selector spool also sends pilot oil to the selector piston that is for first gear (reverse). The rotary selector spool can also send pilot oil to the selector piston that is for second gear (reverse). The pilot oil to the selector piston is also sent to the lube selector spool. This will move the lube selector spool to the right for normal lubrication flow.
The lube selector spool is held in position while you inch the machine in reverse. This happens because the pilot oil pressure does not decrease during inching the machine. The extra oil for the slipping clutch (reverse) comes from the inching lube passage that is for the No. 1 and No. 2 clutches. The additional lube flow is directed to the No. 8 clutch by a slider on the clutch shaft. The slider is moved by the clutch piston. This will open additional passages for lube flow to the clutch.