© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Publisher The Goodheart-Willcox Co., Inc. Tinley Park, Illinois by Russell Krick

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only  Automatic transmission identification  Automatic transmission diagnosis  Automatic transmission maintenance  Major transmission service

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only  The exact type can usually be found in the VIN (vehicle identification number) or on the transmission case  Refer to the service manual to decode the number on the transmission

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only  Common symptoms of transmission problems:  slippage  incorrect shift points  mushy or harsh shifts  noise

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Transmission Problems

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Transmission Slippage  Partial slippage  the engine may race briefly while shifting  Severe slippage  the vehicle may not move  Common causes:  low oil level  misadjusted linkage  worn clutches or bands  valve body problems

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Incorrect Shift Points  The transmission shifts too early or too late  Common causes:  low oil level  faulty modulator  engine performance problem  governor problem  vehicle speed sensor circuit problem  valve, servo, or piston problems

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Transmission Noise  Common causes:  improper oil level  planetary gear troubles  damaged bearings  faulty torque converter  faulty oil pump

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Follow an orderly procedure when diagnosing problems

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Check Oil Level Feel, inspect, and smell the fluid Do not overfill; it only takes a pint of fluid to raise the level from add to full

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Oil Condition  Burned oil will be black or brown  caused by friction material failure due to slippage and overheating  Milky oil indicates coolant mixing with the oil  caused by oil cooler leaking antifreeze into the oil  Varnish is a light brown coating  oil is broken down, requiring an oil change and possible transmission repair

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Check Engine Condition  Engine should start properly, idle smoothly, and perform normally  Check the manifold vacuum and inspect for vacuum leaks if the vacuum is low  engine mechanical problems such as retarded cam timing can cause low vacuum  a plugged catalytic converter can cause poor acceleration and low vacuum, upsetting shifts

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Check Linkages, Cables, and Lines

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Check Electrical Connections  Check sensor and actuator connections  Look for disconnected or frayed wires, corroded connectors, and other basic problems

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Road Testing  Drive the vehicle, checking the general transmission operation  Observe the shift points  Listen for noises  With the transmission in drive, accelerate normally, then repeat while shifting manually through the gear ranges

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Stall Test  Detects transmission slippage or a malfunctioning torque converter  To test:  connect a tachometer  engage the emergency brake and apply the brakes firmly  start the engine and shift into low gear  press the accelerator slowly to the floor

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Performing the Stall Test

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Stall Test Results  Engine speed should level out at a specified rpm  Repeat briefly in each gear position  Engine speed too high  the transmission is slipping  Engine speed too low  torque converter or engine performance problem

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Useful for diagnosis when slippage occurs

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Pressure Tests Used to determine whether the oil pressure in the circuits is normal Ports are provided for gauge installation

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Pressure Tests  To test:  connect a 300 psi (2000 kPa) gauge to the line pressure port  run the engine to operating temperature  while applying the brakes, shift through all the gears while noting the pressures  compare the readings to specs

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Pressure Test Setup

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Air Test  Used to further isolate problems  To test:  remove the oil pan and valve body  use a rubber-tipped nozzle to blow shop air into the transmission passages  25–35 psi (170–240 kPa) is used  activate servos and clutches

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Performing an Air Test A dull thud should be heard A hissing sound indicates a leak

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Service Manual Illustration Useful when performing an air test

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Hydraulic Circuit Diagrams  Show how oil passages are connected to each component  Used when tracing hard-to-find problems  One diagram is given for each gear range  Each diagram is followed by a written description of the circuit operation

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Hydraulic Circuit Diagram

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Electrical Tests  Involves checking sensors, actuators, and wiring  Solenoid testing  use an ohmmeter to check the resistance of the winding and to verify no short-to- ground  Vehicle speed sensor testing  test with a multimeter or oscilloscope

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Vacuum Test  Measures vacuum reaching the valve  To test:  connect a vacuum gauge to the modulator line with a T-fitting  at idle, the reading should match manifold vacuum (high and steady)  If the reading is low, a vacuum leak may be present, the line may be blocked, or the modulator diaphragm may be ruptured

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only  Maintenance is very important to the life of the transmission  Oil can become filled with foreign matter, such as bits of metal, friction material, water, or dust  Impurities in the oil can cause premature wear

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Changing Transmission Oil  Carefully drain the oil  Caution! The oil may be hot  On some transmissions, it may be necessary to drain the torque converter  See the service manual for details

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Changing Transmission Oil Remove the pan

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Changing Transmission Oil Debris in the pan may indicate problems

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Changing Transmission Oil

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Changing Transmission Oil

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Changing Transmission Oil  Fill the transmission with the correct amount and type of oil  Start the engine  Shift through all gears  Check for leaks

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Fluid Oil Leaks  Common leak locations:  rear seal  front seal  oil pan gasket  extension housing gasket  shift lever shaft seal  The transmission will be cleanest nearest to the source of the leak  oil washes the case where it is wettest

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Fluid Oil Leaks The engine rear seal and transmission front seal may drip from the same location

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Band Adjustment  Sets the correct clearance between the band and drum  Clearance too large  the band could slip  Clearance too tight  the band could drag and burn

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Band Adjustment  Loosen the locknut  Turn the adjustment screw on the side of the case to the specified torque  Back off a specified amount, such as one turn, to provide the proper clearance  Tighten the locknut

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Shift Linkage Adjustment Position the shifter and the lever on the transmission in the same gear

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Neutral Safety Switch Adjustment  May be needed if the engine does not crank when the shift selector is in park  Loosen the fasteners  Turn the key to crank with the transmission in park  Slide the switch  As soon as the engine cranks, lock down the switch

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Testing the Switch  Connect an ohmmeter across the switch  The meter should read low resistance (zero ohms) with the switch in park or neutral  The meter should read infinite resistance in all other gear positions  When using a test light, the output terminal should have power in park or neutral

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Electronic Control System Service  Electronically controlled transmissions can suffer conventional problems, as well as electronic problems  Keep mechanical, hydraulic, and electrical malfunctions in mind when troubleshooting

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Knowing each part’s function will help with diagnosis

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Limp-in Mode  Most electronic transmissions have a limp-in mode  Allows the transmission to function if there is a control system failure such as a sensor, solenoid, or wiring problem  Transmission may have only second gear, reverse, neutral, and park  Allows the vehicle to be driven to a repair facility

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Diagnosis  A scan tool may be used to analyze electronic transmissions  If the malfunction indicator lamp is on, connect the scan tool to the data link connector  Check for stored diagnostic trouble codes or abnormal electrical values

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Vehicle Speed Sensor Most can be serviced without transmission removal

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Solenoids Most are on the valve body Remove the pan for service

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Oil Temperature Sensor  Sensor data is used by the TCM or PCM  Since oil viscosity changes with temperature, the computer can alter shift characteristics to maintain shift quality regardless of transmission temperature  If the transmission acts up when hot or cold only, check the sensor circuit

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Sensor Removal A special socket is needed to remove some sensors

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only If tests point to major problems, the transmission may need to be removed, repaired or replaced, and reinstalled

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only  Similar to manual transmission removal  Remove the drive shaft  Remove all wires, lines, and cables  Disconnect the rear transmission mount  Remove any obstructions, such as exhaust parts  Remove the torque converter fasteners Transmission Removal

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Support the transmission with a transmission jack before removing bell housing bolts Transmission Removal

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Transmission Removal

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Usually, specialized technicians perform the work Transmission Rebuild

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Transmission Rebuild When rebuilding, refer to service manual procedures and diagrams

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Transmission Dynamometer After a rebuild, a transmission is tested on a dynamometer

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Torque Converter Installation  Make sure the torque converter is fully in place in the front of the transmission  Usually, the converter must slide over the internal parts twice to be fully inserted  If the torque converter is not fully installed, severe front pump and converter damage will result

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Torque Converter Installation

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only Transmission Installation  Push the transmission into the engine while wiggling the tailshaft  Make sure the torque converter studs fit through the flywheel holes  When the bell housing is touching the engine block, install the bell housing bolts and torque them to specs

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only The transmission must be perfectly aligned with the engine Transmission Installation

© Goodheart-Willcox Co., Inc. Permission granted to reproduce for educational use only  Tighten the torque converter fasteners  Reinstall all linkages, wires, mounts, and lines  Reinstall the drive shaft  Fill the transmission with the proper amount and type of oil  Road test to verify repairs  Check for leaks Transmission Installation