1. La democracia en México
1.1 Algunos obstáculos para la democracia
NOTE
The engine and transmission must be regarded as a single package during troubleshooting. A thorough study of the description and operation of the com-ponents and hydraulic system will be helpful in de-termining the cause of trouble.
a. Before Removal or Operation
1. Do not operate the equipment prior to inspect-ing for fluid leakage. Visually inspect all split-lines, plugs, and hose and tube connections at the transmission and cooler. Fluid leakage at splitlines may be caused by loose mounting bolts or defective gaskets. Tighten all bolts, plugs, and connections where leakage is found.
2. If inspection (Paragraph 3–23a) does not re-veal the cause of trouble, and the equipment is operational, further troubleshooting is neces-sary. Do not remove the transmission from the equipment until the causes of trouble are checked against Table 3–3, Troubleshooting.
b. During Operation. To make a thorough test of the equipment-mounted transmission, be sure the en-gine is properly tuned and the fluid level in the trans-mission is correct. Refer to Paragraph 3–4 for check-ing the fluid level.
c. After Removal From Equipment. When the cause of transmission malfunction is not determined by tests or inspections before removal from the equip-ment, the transmission may be mounted in a test stand (if available) and checked. Particular attention should be given to proper fluid level and to correct linkage ad-justment in every transmission test.
d. Troubleshooting Table. Table 3–3 outlines the possible causes of transmission troubles and their rem-edies. Capital letters indicate the symptom; numerals following the symptom indicate several possible causes; corresponding numerals in the right column indicate remedies for the causes and direct you to in-formation.
Table 3–3. Troubleshooting
Cause Remedy
A. TRANSMISSION OVERHEATS
1. High or low fluid level 1. Restore proper fluid level (Paragraph 3–4).
2. Aerated (foaming) fluid 2. Refer to B.
3. Equipment overloaded 3. Reduce load.
4. Engine coolant overheated 4. Correct engine overheating.
5. Heat exchanger or lines kinked or clogged 5. Clean or replace heat exchanger or lines.
6. Low coolant level 6. Add coolant, check for leaks.
7. Transmission fluid leaking 7. Check transmission and all external lines — correct leaks.
8. Low main pressure 8. Refer to V.
9. Low converter-out pressure 9. Refer to U.
10. Equipment brakes dragging 10. Check parking and service brakes.
11. Torque converter stator locked 11. Check for low top speed of equipment. Check torque converter components.
12. Clutch slipping 12. Overhaul transmission. Replace worn piston
sealrings or clutch plates.
13. Operating in too high range (engine lugging) for equipment speed
13. Downshift sooner to a lower range.
14. Retarder partially applied 14. Check retarder linkage.
B. TRANSMISSION FLUID IS AERATED (FOAMING)
1. Incorrect type fluid used 1. Change fluid; use proper type (Paragraph 3–6).
2. High or low fluid level 2. Restore proper fluid level (Paragraph 3–4).
3. Air entering suction side of pump 3. Check pump bolts and gasket.
4. Water in transmission fluid 4. Check for source; clean system.
C. HEAVY METAL DEBRIS IS FOUND IN TRANSMISSION FLUID
1. Transmission internal failure 1. Completely disassemble, clean, and repair transmission. Replace filters and clean external lines and cooler.
D. COOLANT IS FOUND IN TRANSMISSION FLUID
1. Heat exchanger leaking 1. Completely disassemble and thoroughly clean transmission. Replace all friction-faced clutch plates. Repair or replace heat exchanger. Replace filters and clean external lines.
E. NO POWER IS TRANSMITTED IN ANY RANGE, REGARDLESS OF SELECTOR POSITION 1. Electrical interruption at initial start-up, during
reverse operation, or after reset procedure after lock-in-range system is activated*
1. Check the following components and replace if faulty:*
• Shift Selector Fuse
• Wiring Harness(es) (Paragraph 3–21b)
• Shift Pattern Generator (SPG) (Paragraph 3–21e)
• 24V Overload Protector (Paragraph 3–21f)
• Throttle Potentiometer (Paragraph 3–21c)
• Shift Selector (Paragraph 3–22)
• Equipment Power Source
• Solenoid(s) (Paragraph 3–21h) 2. Electrical interruption at initial start-up, during
reverse operation, or after engine has been started up after lock-in-range system is activated**
2. Check the following components and replace if faulty:**
• Wiring Harness (Paragraph 3–20b)
• Shift Selector Fuse
• Shift Selector (Paragraph 3–22)
• Equipment Power Source
• Solenoid(s) (Paragraph 3–20c) 3. Electrical interruption at initial start-up or during
operation***
3. Refer to E2.
4. Internal mechanical failure 4. Overhaul transmission.
* SPG-control automatic-electric models only.
** Non-electronic control models; for electronic controls, see SA2712.
*** Only manual-electric models with Lock-in-Neutral.
Table 3–3. Troubleshooting (cont’d)
Cause Remedy
E. NO POWER IS TRANSMITTED IN ANY RANGE, REGARDLESS OF SELECTOR POSITION (cont’d)
5. Driveline failure 5. Check input and output of transmission.
6. Low fluid level 6. Restore proper fluid level (Paragraph 3–4).
7. Low main pressure 7. Refer to V.
8. Manual selector valve not positioned properly (manual-hydraulic models)
8. Check linkage.
F. TRANSMISSION CONTINUES IN THE SAME FORWARD RANGE REGARDLESS OF SELECTOR POSITION
1. Lock-in-range system activated* 1. Conduct reset procedures. After reset procedures, be sure transmission is actually in range selected before increasing throttle.
• If after reset, transmission operates only in first, neutral, and reverse, refer to H.
• If after reset, transmission operates erratically, refer to G.
• If after reset, transmission remains in neutral, regardless of selector position, check the components listed in E1.
2. Complete electrical interruption, lock-in-range system activated**
2. Shut down engine and check the components listed in E2.**
G. SHIFTING IS ERRATIC†
1. Power source voltage under 18V or faulty 24V overload protector (24V system); or, power source voltage under 9V or faulty 12V-to-24V converter
1. Check terminals 1 and 2 (Figures 2–5, 2–6) of overload protector (24V system). If under 18V, restore power source. Check terminals 1 and 2 (Figures 2–5, 2–6) of 12V-to-24V converter (12V systems). If under 9V, restore power source.
Check voltage at terminals 3 and 4 of the 24V overload protector or the 12V-to-24V converter.
If under 18V and the power source voltage is OK, replace the overload protector or converter.
* SPG-control automatic-electric models only.
** Only manual-electric models with Lock-in-Range.
† Non-electronic control models; for electronic controls, see SA2712.
Table 3–3. Troubleshooting (cont’d)
Cause Remedy
G. SHIFTING IS ERRATIC† (cont’d)
2. Wiring harness(es) or mating connectors faulty 2. Check all wiring harness(es) for breaks, signs of chafing, fraying, or deterioration.
• Check all connections for tightness and freedom from corrosion.
• Disconnect, clean, and reconnect any defective connections. Firm, complete connection of each connector is important.
The pins must not be bent or otherwise damaged.
• Align the index key and slot, and push the cable end of the connector firmly into its socket. Tighten the retaining nut as tightly as possible, by hand (do not use any tool to retain the connectors).
• Then push again on the cable end while working it slightly from side to side and retighten the nut.
• Continue pushing the cable end and tightening the nut until the connection is firm, and the nut will not tighten further.
• Refer to Paragraph 3–20b or 3–21b to test wiring harness — replace if faulty.
3. Loss of electrical power to controlling solenoids 3. Check circuit(s) and solenoid(s) and replace if faulty (Paragraphs 3–20c, 3–21h).
4. Faulty shift selector 4. Check shift selector — repair if faulty (Paragraph 3–22).
5. Faulty throttle potentiometer†† 5. Check throttle potentiometer — repair or replace if faulty (Paragraph 3–21c).††
6. Faulty magnetic pickup†† 6. Check magnetic pickup — replace if faulty (Paragraph 3–21d).††
7. Faulty shift pattern generator (SPG)†† 7. Check SPG — repair or replace if faulty (Paragraph 3–21e).††
8. Faulty hydraulic circuits 8. Check hydraulic circuits — correct faults (Paragraph 3–20d, 3–21i).
† Non-electronic control models; for electronic controls, see SA2712.
†† Automatic-electric models only.
Table 3–3. Troubleshooting (cont’d)
Cause Remedy
H. EQUIPMENT OPERATES ONLY IN FIRST, NEUTRAL, AND REVERSE
1. Failed magnetic pickup (speed sensor) or circuit 1. Replace magnetic pickup (speed sensor) or repair circuit.
I. TRANSMISSION SHIFTS TO NEUTRAL DURING REVERSE OPERATION, BUT WILL OPERATE NORMALLY IN ALL FORWARD RANGES
1. Loss of electrical power to Solenoid B 1. Repair circuit or replace Solenoid B.
J. EQUIPMENT OPERATES IN REVERSE AND MOVES BACKWARD IN NEUTRAL WHEN ENGINE IS ACCELERATED, BUT STALLS IN ALL OTHER RANGES WHEN ENGINE IS ACCELERATED. SOLENOIDS OK.
1. Reverse clutch failed (won’t release) 1. Overhaul transmission.
K. EQUIPMENT OPERATES IN FIRST AND SECOND RANGES AND MOVES FORWARD IN NEUTRAL WHEN ENGINE IS ACCELERATED, BUT STALLS IN ALL OTHER RANGES WHEN ENGINE IS ACCELERATED. SOLENOIDS OK.
1. Low-range clutch failed (won’t release) 1. Overhaul transmission.
L. EQUIPMENT OPERATES IN THIRD AND FOURTH RANGES AND MOVES FORWARD IN NEUTRAL WHEN ENGINE IS ACCELERATED, BUT STALLS IN ALL OTHER RANGES WHEN ENGINE IS ACCELERATED. SOLENOIDS OK.
1. Intermediate-range clutch failed (won’t release) 1. Overhaul transmission.
M. EQUIPMENT OPERATES IN FIFTH AND SIXTH RANGES AND MOVES FORWARD IN NEUTRAL WHEN ENGINE IS ACCELERATED, BUT STALLS IN ALL OTHER RANGES WHEN ENGINE IS ACCELERATED. SOLENOIDS OK.
1. High-range clutch failed (won’t release) 1. Overhaul transmission.
N. NO POWER IS TRANSMITTED IN ONE RANGE (LOW RANGE, INTERMEDIATE RANGE, HIGH RANGE, OR REVERSE). SOLENOIDS OK.
1. Range clutch failed (won’t apply, slipping) 1. Overhaul transmission. Check for worn piston seals, broken piston housing, or worn clutch plates in that range.
2. Manual selector linkage out of adjustment* 2. Adjust linkage.*
* Manual-hydraulic models only.
Table 3–3. Troubleshooting (cont’d)
Cause Remedy
O. EQUIPMENT WILL OPERATE IN SECOND, FOURTH, AND SIXTH RANGES BUT WILL NOT OPERATE IN ALL OTHER RANGES. SOLENOIDS OK.
1. Splitter shift valve stuck in the splitter-high (down) position
1. Remove and clean control valve assembly. Check for broken spring.
P. EQUIPMENT WILL OPERATE IN FIRST, THIRD, FIFTH, AND REVERSE RANGES BUT WILL NOT OPERATE IN ALL OTHER RANGES. SOLENOIDS OK.
1. Splitter shift valve stuck in the splitter-low (up) position
1. Remove and clean control valve assembly.
Q. SLOW CLUTCH ENGAGEMENT
1. Low transmission fluid level 1. Add fluid to proper level (Paragraph 3–4).
2. Foaming transmission fluid 2. Refer to B.
3. Worn piston seals 3. Overhaul transmission.
4. Low main pressure 4. Refer to V.
5. Low transmission fluid temperature 5. Use recommended fluid (Paragraph 3–6a).
Preheat if required.
R. EQUIPMENT LACKS POWER AND ACCELERATION
1. Defective or failed torque converter 1. Overhaul torque converter.
2. Engine malfunction 2. Check engine; refer to engine service manual.
3. Aerated transmission fluid 3. Refer to B.
4. Low engine speed at converter stall 4. Refer to T.
5. High engine speed at converter stall 5. Refer to S.
6. Hydraulic retarder partially applied 6. Check linkage (Paragraph 3–12).
7. Vehicle brakes dragging 7. Check parking and service brakes.
8. Manual selector valve not positioned properly* 8. Check linkage (Paragraph 3–12a).
S. HIGH ENGINE SPEED AT CONVERTER STALL (Paragraph 3–16)
1. Low transmission fluid level 1. Add fluid to proper level (Paragraph 3–4).
2. Low converter-out pressure 2. Refer to U.
* Manual-hydraulic models only.
Table 3–3. Troubleshooting (cont’d)
Cause Remedy
S. HIGH ENGINE SPEED AT CONVERTER STALL (Paragraph 3–16) (cont’d) 3. High fluid temperature (above 250˚F (121˚C)) 3. Refer to Paragraph 3–11a.
4. Clutch slipping — main pressure normal 4. Overhaul transmission. Replace clutch piston sealrings or clutch plates.
5. Foaming transmission fluid 5. Refer to B.
T. LOW ENGINE SPEED AT CONVERTER STALL (Paragraph 3–16)
1. Low engine output torque 1. Tune engine and check output.
2. Converter element interference 2. Check for noise at stall; overhaul converter if necessary.
3. Transmission fluid not up to operating temperature
3. Warm up transmission to 160–200˚F (71–93˚C).
U. LOW CONVERTER-OUT PRESSURE
1. Low transmission fluid level 1. Add fluid to proper level (Paragraph 3–4).
2. Hydraulic line leakage (remote-mounted cooler or filter)
2. Check for fluid leaks. Correct leaks.
3. Plugged strainer 3. Clean strainer.
4. Defective pump 4. Rebuild or replace pump assembly
(Paragraph 6–28).
5. High fluid temperature 5. Refer to Paragraph 3–11a.
6. Foaming transmission fluid 6. Refer to B.
7. Converter-in check valve stuck open or spring failed
7. Repair valve (Paragraph 6–29).
8. Lubrication regulator valve stuck open or spring failed
8. Repair valve (Paragraph 6–29).
V. LOW MAIN PRESSURE
1. Low transmission fluid level 1. Add fluid to proper level (Paragraph 3–4).
2. Leaks in hydraulic system 2. Check all external points for leaks; check each range for localizing internal leaks.
3. Failure in main-pressure regulator valve 3. Overhaul valve assembly (Paragraph 6–13).
4. Worn input pump assembly 4. Rebuild or replace pump assembly (Paragraph 6–28).
5. Clogged strainer 5. Clean strainer.
6. Air leaks at suction side of input pump 6. Check input pump; correct leaks.
Table 3–3. Troubleshooting (cont’d)
Cause Remedy
W. DOWNSHIFT OF TRANSMISSION IS PERMITTED DURING LOCKUP OPERATION*
1. Disconnected or broken wiring harness lead to the inhibitor pressure switch
1. Inspect the wiring harness lead and ground lead (or terminal if no ground lead is used) for corrosion, loose connection, and condition.
2. Failed pressure switch 2. With equipment power on, ground the inhibitor wiring harness lead to the body of the pressure switch. If the inhibitor then engages, the pressure switch is faulty (will not close) and should be replaced.
3. Faulty shift selector 3. If grounding the lead does not actuate the inhibitor, check the shift selector (Paragraph 3–22).
4. Faulty wiring harness 4. Check wiring harness; replace if faulty (Paragraph 3–20b).
X. SHIFT SELECTOR STAYS LOCKED IN PLACE, REGARDLESS OF EQUIPMENT SPEED*
1. Improperly grounded wiring harness lead to the pressure switch
1. Check the pressure switch lead for a ground.
Check that the lead is connected to the pressure switch terminal insulated with a fiber washer (not to the terminal having a star washer).
2. Failed pressure switch 2. If disconnecting the pressure switch lead from the switch terminal disengages the inhibitor, the pressure switch is faulty and must be replaced.
3. Faulty shift selector 3. Check the shift selector (Paragraph 3–22). The inhibitor should engage when the lead to pressure switch K (Figure 3–7) is grounded (while equipment power to the selector is on).
4. Faulty wiring harness 4. Check wiring harness. Replace if faulty (Paragraph 3–20b).
Y. SHIFT SELECTOR NOT ILLUMINATED**
1. Failed light bulb 1. Replace the light bulb.
2. Failed resistor (24V system) 2. Replace the resistor.
3. Defective equipment wiring or connections or defective wiring harness(es)
3. Check the equipment wiring and terminals; refer to the equipment wiring diagram. Check wiring harness(es) (Paragraphs 3–20b, 3–21b). Replace if faulty.
4. Faulty shift selector 4. Check the shift selector. Repair if faulty (Paragraph 3–22).
* Manual-electric models only.
** Non-electronic control models; for electronic controls, see SA2712.
Table 3–3. Troubleshooting (cont’d)
Cause Remedy
Z. REVERSE SIGNAL NOT ENERGIZED**
1. Failed reverse indicator device, faulty connectors 1. Check the reverse indicator device. Check for power to the indicator.
2. Defective equipment wiring or connections 2. Check the equipment wiring system for loose connections or broken wires and connectors;
refer to equipment wiring diagrams.
3. Faulty shift selector 3. Check the shift selector. Repair if faulty (Paragraph 3–22).
4. Faulty wiring harness 4. Check wiring harness. Replace if faulty (Paragraphs 3–20b, 3–21b).
AA. STARTER OPERATES IN ALL RANGES**
1. Faulty neutral start switch 1. Replace neutral start switch in shift selector (Paragraphs 6–3, 6–5).
AB. STARTER WILL NOT OPERATE IN NEUTRAL*
1. Faulty starter or starter solenoid 1. Using a test light or voltmeter, check for power at the starter solenoid input when the starter switch is activated. If power is present, the starter or solenoid is defective. If no power is present, go to Step 2.
2. Disconnected or broken wire or terminal in the equipment wiring system
2. Check the equipment wiring system. Refer to the equipment service manual.
3. Faulty shift selector 3. Check the shift selector. Repair if bad (Paragraph 3–22).
AC. LOSS OF POWER AT EQUIPMENT-FURNISHED PTO (Models With Variable-Capacity Torque Converter)
1. Defective actuation 1. Repair or replace actuation device and/or control components.
2. Weak or broken stator control spring 2. Replace spring (Paragraph 3–11g).
3. Defective stator control valve assembly 3. Rebuild stator control valve assembly (Paragraph 6–12).
* Manual-electric models only.
** Non-electronic control models; for electronic controls, see SA2712.
Table 3–3. Troubleshooting (cont’d)
Cause Remedy
AC. LOSS OF POWER AT EQUIPMENT-FURNISHED PTO (Models With Variable-Capacity Torque Converter) (cont’d) 4. External transmission fluid leakage (stator
control circuit)
4. Tighten or replace hydraulic lines.
5. Internal transmission fluid leaks (stator control circuit)
5. Overhaul transmission.
6. Stuck stator piston or stator vanes 6. Rebuild stator (Paragraph 6–26).
7. Defective stator piston seals 7. Replace piston seals (Paragraph 6–26).
AD. LOSS OF TRACTIVE EFFORT (Models With Variable-Capacity Torque Converter)
1. Defective actuation 1. Repair or replace actuation device and/or control components.
2. Stator control valve spring broken or missing 2. Replace spring (Paragraph 3–11g).
3. Defective stator control valve 3. Rebuild stator control valve assembly (Paragraph 6–12).
4. Stuck stator piston or stator vanes 4. Rebuild stator piston (Paragraph 6–26).
Table 3–3. Troubleshooting (cont’d)
Cause Remedy
4–1. SCOPE
a. This section provides general information for overhaul, cleaning, and inspection of the transmission.
Tables include special tools and recommended re-placement of parts. Good shop practices together with the recommended procedures will aid in restoring high quality performance.
b. For electronic control transmissions, refer to TS2712EN, Troubleshooting Manual, for special tools and procedures.