Toyota
Jeep Cherokee
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Transmission and transfer case » Automatic transmission-30RH » Diagnosis and testing
Diagnosis charts

The diagnosis charts provide additional reference when diagnosing a transmission fault. The charts provide general information on a variety of transmission, overdrive unit and converter clutch fault conditions.

The hydraulic flow charts, in the Schematics and Diagrams section of this group, outline fluid flow and hydraulic circuitry. Circuit operation is provided for neutral, third, fourth and reverse gear ranges. Normal working pressures are also supplied for each of the gear ranges.

DIAGNOSIS CHART

CONDITION

POSSIBLE CAUSES

CORRECTION

HARSH ENGAGEMENT FROM NEUTRAL TO DRIVE OR REVERSE
  1. Fluid Level Low
  2.  Throttle Linkage Misadjusted
  3.  Mount and Driveline Bolts Loose
  4.  U-Joint Worn/Broken
  5.  Axle Backlash Incorrect
  6.  Hydraulic Pressure Incorrect
  7.  Band Misadjusted.
  8.  Valve Body Check Balls Missing.
  9.  Axle Pinion Flange Loose.
  10.  Clutch, band or planetary component Damaged.
  11.  Converter Clutch (if equipped) Faulty.
  1.   Add Fluid
  2.  Adjust linkage - setting may be too long.
  3. Check engine mount, transmission mount, propeller shaft, rear spring to body bolts, rear control arms, crossmember and axle bolt torque. Tighten loose bolts and replace missing bolts.
  4. Remove propeller shaft and replace U-Joint.
  5. Check per Service Manual. Correct as needed.
  6. Check pressure. Remove, overhaul or adjust valve body as needed.
  7. Adjust rear band.
  8. Inspect valve body for proper check ball installation.
  9. Replace nut and check pinion threads before installing new nut. Replace pinion gear if threads are damaged.
  10.  Remove, disassemble and repair transmission as necessary.
  11.  Replace converter and flush cooler and line before installing new converter.
DELAYED ENGAGEMENT FROM NEUTRAL TO DRIVE OR REVERSE
  1. Fluid Level Low.
  2.  Filter Clogged.
  3.  Gearshift Linkage Misadjusted.
  4.  Rear Band Misadjusted.
  5.  Valve Body Filter Plugged.
  6. Oil Pump Gears Worn/Damaged.
  7.  Hydraulic Pressure Incorrect.
  8. Reaction Shaft Seal Rings Worn/Broken.
  9.  Rear Clutch/Input Shaft, Rear Clutch Seal Rings Damaged.
  10.  Governor Valve Stuck.
  11.  Regulator Valve Stuck.
  12.  Cooler Plugged.
  1.  Correct level and check for leaks.
  2. Change filter.
  3. Adjust linkage and repair linkage if worn or damaged.
  4. Adjust band.
  5. Replace fluid and filter. If oil pan and old fluid were full of clutch disc material and/or metal particles, overhaul will be necessary.
  6. Remove transmission and replace oil pump.
  7. Perform pressure test, remove transmission and repair as needed.
  8. Remove transmission, remove oil pump and replace seal rings.
  9. Remove and disassemble transmission and repair as necessary.
  10. Remove and inspect governor components. Replace worn or damaged parts.
  11.  Clean.
  12.  Flush transmission cooler and inspect convertor drainback valve.
NO DRIVE RANGE (REVERSE OK)
  1. Fluid Level Low.
  2.  Gearshift Linkage/Cable Loose/Misadjusted.
  3.  Rear Clutch Burnt.
  4.  Valve Body Malfunction.
  5.  Transmission Overrunning Clutch Broken.
  6.  Input Shaft Seal Rings Worn/ Damaged.
  7. Front Planetary Failed Broken.
  1.  Add fluid and check for leaks if drive is restored.
  2.  Repair or replace linkage components.
  3. Remove and disassemble transmission and rear clutch and seals. Repair/replace worn or damaged parts as needed.
  4.  Remove and disassemble valve body. Replace assembly if any valves or bores are damaged.
  5.  Remove and disassemble transmission. Replace overrunning clutch.
  6.  Remove and disassemble transmission. Replace seal rings and any other worn or damaged parts.
  7.  Remove and repair.
NO DRIVE OR REVERSE (VEHICLE WILL NOT MOVE)
  1. Fluid Level Low.
  2.  Gearshift Linkage/Cable Loose/Misadjusted.
  3.  U-Joint/Axle/Transfer Case Broken.
  4.  Filter Plugged.
  5. Oil Pump Damaged.
  6.  Valve Body Malfunctioned.
  7.  Transmission Internal Component Damaged.
  8.  Park Sprag not Releasing
  9.  Torque Converter Damage.
  1.  Add fluid and check for leaks if drive is restored.
  2.  Inspect, adjust and reassemble linkage as needed. Replace worn/damaged parts.
  3.  Perform preliminary inspection procedure for vehicle that will not move. Refer to procedure in diagnosis section.
  4. Remove and disassemble transmission. Repair or replace failed components as needed. Replace filter. If filter and fluid contained clutch material or metal particles, an overhaul may be necessary. Perform lube flow test. Flush oil. Replace cooler as necessary.
  5. Perform pressure test to confirm low pressure. Replace pump body assembly if necessary.
  6. Check press and inspect valve body. Replace valve body (as assembly) if any valve or bore is damaged. Clean and reassemble correctly if all parts are in good condition.
  7.  Remove and disassemble transmission. Repair or replace failed components as needed. Remove and disassemble transmission. Repair or replace failed components as needed.
  8. Remove, disassemble, repair.
  9. Check Stall Speed, Worn/Damaged/ Stuck. Inspect and replace as required.
SHIFTS DELAYED OR ERRATIC (SHIFTS ALSO HARSH AT TIMES)
  1. Fluid Level Low/High.
  2.  Throttle Linkage Misadjusted.
  3.  Throttle Linkage Binding.
  4.  Gearshift Linkage/Cable Misadjusted.
  5.  Fluid Filter Clogged.
  6.  Governor Valve Sticking.
  7.  Governor Seal Rings Worn/ Damaged.
  8.  Clutch or Servo Failure.
  9.  Front Band Misadjusted.
  10.  Pump Suction Passage Leak.
  1.  Correct fluid level and check for leaks if low.
  2.  Adjust linkage as described in service section.
  3.  Check cable for binding. Check for return to closed throttle at transmission.
  4.  Adjust linkage/cable as described in service section.
  5.  Replace filter. If filter and fluid contained clutch material or metal particles, an overhaul may be necessary. Perform lube flow test.
  6. Inspect, clean or repair.
  7.  Inspect/replace.
  8. Remove valve body and air test clutch, and band servo operation. Disassemble and repair transmission as needed.
  9. Adjust band.
  10. Check for excessive foam on dipstick after normal driving. Check for loose pump bolts, defective gasket. Replace pump assembly if needed.
NO REVERSE (D RANGES OK)
  1. Gearshift Linkage/Cable Misadjusted/Damaged.
  2.  Park Sprag Sticking.
  3.  Rear Band Misadjusted/Worn.
  4.  Valve Body Malfunction.
  5.  Rear Servo Malfunction.
  6.  Front Clutch Burnt.
  1.  Repair or replace linkage parts as needed.
  2.  Inspect and replace as necessary.
  3. Adjust band; replace.
  4. Remove and service valve body. Replace valve body if any valves or valve bores are worn or damaged.
  5. Remove and disassemble transmission. Replace worn/damaged servo parts as necessary.
  6. Remove and disassemble transmission. Replace worn, damaged clutch parts as required.
HAS FIRST/REVERSE ONLY (NO 1-2 OR 2-3 UPSHIFT)
  1. Governor Valve, Shaft, Weights or Body Damaged/Stuck.
  2.  Valve Body Malfunction.
  3.  Front Servo/Kickdown Band Damaged/Burned.
  1.  Remove governor assembly and clean or repair as necessary.
  2. Stuck 1-2 shift valve or governor plug.
  3.  Repair/replace.
MOVES IN 2ND OR 3RD GEAR, ABRUPTLY DOWNSHIFTS TO LOW
  1. Valve Body Malfunction.
  2. Governor Valve Sticking.
  1.  Remove, clean and inspect. Look for stuck 1-2 valve or governor plug.
  2. Remove, clean and inspect. Replace faulty parts.
NO LOW GEAR (MOVES IN 2ND OR 3RD GEAR ONLY)
  1. Governor Valve Sticking.
  2.  Valve Body Malfunction.
  3.  Front Servo Piston Cocked in Bore.
  4. Front Band Linkage Malfunction
  1.  Remove governor, clean, inspect and repair as required.
  2. Remove, clean and inspect. Look for sticking 1-2 shift valve, 2-3 shift valve, governor plug or broken springs.
  3.  Inspect servo and repair as required.
  4. Inspect linkage and look for bind in linkage.
NO KICKDOWN OR NORMAL DOWNSHIFT
  1. Throttle Linkage Misadjusted.
  2.  Accelerator Pedal Travel Restricted.
  3.  Governor/Valve Body Hydraulic Pressures Too High or Too Low Due to Sticking Governor, Valve Body Malfunction or Incorrect Hydraulic Control Pressure Adjustments.
  4.  Valve Body Malfunction.
  5. Valve Body Malfunction.
  1. Adjust linkage.
  2.  Floor mat under pedal, accelerator cable worn or brackets bent.
  3.  Perform hydraulic pressure tests to determine cause and repair as required. Correct valve body pressure adjustments as required.
  4. Perform hydraulic pressure tests to determine cause and repair as required. Correct valve body pressure adjustments as required.
  5. Sticking 1-2, 2-3 shift valves, or governor plugs.
STUCK IN LOW GEAR (WILL NOT UPSHIFT)
  1. Throttle Linkage Misadjusted/ Stuck.
  2. Gearshift Linkage Misadjusted.
  3.  Governor/Valve Body, Governor Valve Stuck Closed; Loose Output Shaft Support or Governor Housing Bolts, Leaking Seal Rings or Valve Body Problem (i.e., Stuck 1- 2 Shift Valve/Gov. Plug).
  4.  Front Band Out of Adjustment.
  5.  Clutch or Servo Malfunction.
  1.  Adjust linkage and repair linkage if worn or damaged. Check for binding cable or missing return spring.
  2. Adjust linkage and repair linkage if worn or damaged.
  3.  Check line and governor pressures to determine cause. Correct as required.
  4. Adjust Band.
  5. Air pressure check operation of clutches and bands. Repair faulty component.
CREEPS IN NEUTRAL
  1. Gearshift Linkage Misadjusted.
  2. Rear Clutch Dragging/Warped Welded.
  3.  Valve Body Malfunction.
  1.  Adjust linkage.
  2. Disassemble and repair.
  3. Perform hydraulic pressure test to determine cause and repair as required.
BUZZING NOISE
  1. Fluid Level Low
  2.  Shift Cable Misassembled.
  3.  Valve Body Misassembled.
  4. Pump Passages Leaking
  5. Cooling System Cooler Plugged.
  6.  Overrunning Clutch Damaged.
  1.  Add fluid and check for leaks.
  2. Route cable away from engine and bell housing.
  3.  Remove, disassemble, inspect valve body. Reassemble correctly if necessary. Replace assembly if valves or springs are damaged. Check for loose bolts or screws.
  4. Check pump for porous casting, scores on mating surfaces and excess rotor clearance. Repair as required. Loose pump bolts.
  5. Flow check cooler circuit. Repair as needed.6. Replace clutch.
SLIPS IN REVERSE ONLY
  1. Fluid Level Low.
  2.  Gearshift Linkage Misadjusted.
  3.  Rear Band Misadjusted.
  4.  Rear Band Worn.
  5.  Hydraulic Pressure Too Low.
  6.  Rear Servo Leaking.
  7.  Band Linkage Binding.
  1.  Add fluid and check for leaks.
  2. Adjust linkage.
  3. Adjust band.
  4. Replace as required.
  5. Perform hydraulic pressure tests to determine cause.
  6.  Air pressure check clutch-servo operation and repair as required.
  7.  Inspect and repair as required.
SLIPS IN FORWARD DRIVE RANGES
  1. Fluid Level Low.
  2.  Fluid Foaming.
  3.  Throttle Linkage Misadjusted.
  4.  Gearshift Linkage Misadjusted.
  5. Rear Clutch Worn.
  6.  Low Hydraulic Pressure Due to Worn Pump, Incorrect Control Pressure Adjustments, Valve Body Warpage or Malfunction, Sticking Governor, Leaking Seal Rings, Clutch Seals Leaking, Servo Leaks, Clogged Filter or Cooler Lines
  7.  Rear Clutch Malfunction, Leaking Seals or Worn Plates.
  8.  Overrunning Clutch Worn, Not Holding (Slips in 1 Only).
  1.  Add fluid and check for leaks.
  2. Check for high oil level, bad pump gasket or seals, dirt between pump halves and loose pump bolts. Replace pump if necessary.
  3. Adjust linkage.
  4.  Adjust linkage.
  5.  Inspect and replace as needed.
  6.  Perform hydraulic and air pressure tests to determine cause.
  7.  Air pressure check clutch-servo operation and repair as required.
  8.  Replace Clutch.
SLIPS IN LOW GEAR "D" ONLY, BUT NOT IN 1 POSITION Overrunning Clutch Faulty. Replace overrunning clutch.
GROWLING, GRATING OR SCRAPING NOISES
  1. Drive Plate Broken.
  2.  Torque Converter Bolts Hitting Dust Shield.
  3.  Planetary Gear Set Broken/ Seized.
  4.  Overrunning Clutch Worn/Broken.
  5.  Oil Pump Components Scored/ Binding.
  6.  Output Shaft Bearing or Bushing Damaged.
  7.  Clutch Operation Faulty.
  8.  Front and Rear Bands Misadjusted.
  1.  Replace.
  2.  Dust shield bent. Replace or repair.
  3.  Check for debris in oil pan and repair as required.
  4. Inspect and check for debris in oil pan. Repair as required.
  5.  Remove, inspect and repair as required.
  6.  Remove, inspect and repair as required.
  7. Perform air pressure check and repair as required.
  8.  Adjust bands.
DRAGS OR LOCKS UP
  1. Fluid Level Low.
  2.  Clutch Dragging/Failed
  3.  Front or Rear Band Misadjusted.
  4.  Case Leaks Internally.
  5.  Servo Band or Linkage Malfunction.
  6.  Overrunning Clutch Worn.
  7.  Planetary Gears Broken.
  8.  Converter Clutch Dragging.
  1.  Check and adjust level.
  2. Air pressure check clutch operation and repair as required.
  3. Adjust bands.
  4. Check for leakage between passages in case.
  5.  Air pressure check servo operation and repair as required.
  6. Remove and inspect clutch. Repair as required.
  7. Remove, inspect and repair as required (look for debris in oil pan).
  8. Check for plugged cooler. Perform flow check. Inspect pump for excessive side clearance. Replace pump as required.
WHINE/NOISE RELATED TO ENGINE SPEED
  1. Fluid Level Low.
  2. Shift Cable Incorrect Routing.
  1.  Add fluid and check for leaks.
  2. Check shift cable for correct routing. Should not touch engine or bell housing.
TORQUE CONVERTER LOCKS UP IN SECOND AND/OR THIRD GEAR Lockup Solenoid, Relay or Wiring Shorted/Open. Test solenoid, relay and wiring for continuity, shorts or grounds. Replace solenoid and relay if faulty. Repair wiring and connectors as necessary
HARSH 1-2 OR 2-3 SHIFTS Lockup Solenoid Malfunction. Remove valve body and replace solenoid assembly.
NO START IN PARK OR NEUTRAL
  1. Gearshift Linkage/Cable Misadjusted.
  2.  Neutral Switch Wire Open/Cut.
  3.  Neutral Switch Faulty.
  4.  Neutral Switch Connect Faulty.
  5.  Valve Body Manual Lever Assembly Bent/Worn/Broken.
  1.  Adjust linkage/cable.
  2. Check continuity with test lamp. Repair as required.
  3. Refer to service section for test and replacement procedure.
  4. Connectors spread open. Repair.
  5.  Inspect lever assembly and replace if damaged.
NO REVERSE (OR SLIPS IN REVERSE)
  1. Direct Clutch Pack (front clutch) Worn.
  2.  Rear Band Misadjusted.
  3.  Front Clutch Malfunctioned/Burnt.
  1.  Disassemble unit and rebuild clutch pack.
  2. Adjust band.
  3. Air pressure test clutch operation. Remove and rebuild if necessary.
OIL LEAKS (ITEMS LISTED REPRESENT POSSIBLE LEAK POINTS AND SHOULD ALL BE CHECKED.
  1. Speedometer Adapter Leaks.
  2.  Fluid Lines and Fittings Loose/ Leaks/Damaged.
  3.  Filler Tube (where tube enters case) Leaks/Damaged.
  4.  Pressure Port Plug Loose Loose/Damaged.
  5.  Pan Gasket Leaks.
  6.  Valve Body Manual Lever Shaft Seal Leaks/Worn.
  7.  Rear Bearing Access Plate Leaks.
  8.  Gasket Damaged or Bolts are Loose.
  9.  Adapter/Extension Gasket Damaged Leaks/Damaged.
  10.  Neutral Switch Leaks/Damaged.
  11.  Converter Housing Area Leaks.
  12.  Pump Seal Leaks/Worn/ Damaged.
  13.  Torque Converter Weld Leak/Cracked Hub.
  14.  Case Porosity Leaks.
  1.  Replace both adapter seals.
  2.  Tighten fittings. If leaks persist, replace fittings and lines if necessary.
  3.  Replace O-ring seal. Inspect tube for cracks in tube.
  4.  Tighten to correct torque. Replace plug or reseal if leak persists.
  5. Tighten pan screws to 150 inch pounds. If leaks persist, replace gasket. Do no over tighten screws.
  6.  Replace shaft seal.
  7. Replace gasket. Tighten screws.
  8.  Replace bolts or gasket or tighten both.
  9. Replace gasket.
  10. Replace switch and gasket.
  11.  Check for leaks at seal caused by worn seal or burr on converter hub (cutting seal), worn bushing, missing oil return, oil in front pump housing or hole plugged. Check for leaks past O-ring seal on pump or past pump-to-case bolts; pump housing porous, oil coming out vent due to overfill or leak past front band shaft access plug.
  12.  Replace seal.
  13.  Replace converter.
  14.  Replace case.
    More about «Diagnosis and testing»:

    Automatic transmission diagnosis

    Effects of incorrect fluid level

    Causes of burnt fluid

    Fluid contamination

    Preliminary diagnosis

    Park/neutral position switch

    Gearshift cable

    Throttle valve cable

    Road testing

    Analyzing road test

    Hydraulic pressure test

    Air testing transmission clutch and band operation

    Converter housing fluid leak diagnosis

    Diagnosis charts

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