Pressure testing is a very important step in the diagnostic procedure. These tests usually reveal the cause of most transmission problems.Before performing pressure tests, be certain that fluid level and condition, and shift cable adjustments have been checked and approved. Fluid must be at operating temperature ,150 to 200 degrees F. ( 65 - 93 degrees C.). Install an engine tachometer, raise vehicle on hoist which allows the wheels to turn, and position tachometer so it can be read.Using special adapters L-4559, attach 300 psi gauge(s) C-3293SP to the port(s) required for test being conducted.Test port locations are shown in the  Pressure Taps graphic.This test checks pump output, pressure regulation and condition of the low/reverse clutch hydraulic circuit and shift schedule.Attach pressure gauge to the low/reverse clutch tap.Move selector lever to the MANUAL 1 position.Allow vehicle wheels to turn and increase throttle opening to achieve an indicated vehicle speed to 20 mph.Low/reverse clutch pressure should read 115 to 145 psi.This test checks the underdrive clutch hydraulic circuit as well as the shift schedule.Attach gauge to the underdrive clutch tap.Move selector lever to the MANUAL 2 position.Allow vehicle wheels to turn and increase throttle opening to achieve an indicated vehicle speed of 30 mph.In second gear the underdrive clutch pressure should read 110 to 145 psi.This test checks the underdrive clutch hydraulic circuit as well as the shift schedule.Attach gauge to the underdrive clutch tap.Move selector lever to the DRIVE position. Verfy that the OD switch is ON.Allow wheels to rotate freely and increase throttle opening to achieve an indicated speed of 40 mph.Underdrive clutch pressure should read below 5 psi. If not, than either the solenoid assembly or controller is at fault.This test checks the overdrive clutch hydraulic circuit as well as the shift schedule.Attach gauge to the overdrive clutch tap.Move selector lever to the DRIVE position.Allow vehicle wheels to turn and increase throttle opening to achieve an indicated vehicle speed of 20 mph.Overdrive clutch pressure should read 74 to 95 psi.Move selector lever to the DRIVE position and increase indicated vehicle speed to 30 mph.The vehicle should be in second gear and overdrive clutch pressure should be less than 5 psi.This test checks the 2/4 clutch hydraulic circuit.Attach gauge to the 2/4 clutch tap.Move selector lever to the DRIVE position.Allow vehicle front wheels to turn and increase throttle opening to achieve an indicated vehicle speed of 30 mph. Vehicle should be in fourth gear.The 2/4 clutch pressure should read 75 to 95 psi.These tests check the torque converter clutch hydraulic circuit.Attach gauge to the torque converter clutch off pressure tap.Move selector lever to the DRIVE position.Allow vehicle wheels to turn and increase throttle opening to achieve an indicated vehicle speed of 50 mph. Vehicle should be in 4th gear, CC on.Both wheels must turn at the same speed.Torque converter clutch off pressure should be less than 5 psi.Now attach the gauge to the torque converter clutch on pressure tap.Move selector to the OD position.Allow vehicle wheels to turn and increase throttle opening to achieve an indicated vehicle speed of 50 mph.Verify the torque converter clutch is applied mode using the RPM display of the DRB scan tool.Torque converter clutch on pressure should be 60-90 psi.This test checks the reverse clutch hydraulic circuit.Attach gauge to the reverse and low/reverse clutch tap.Move selector lever to the REVERSE position.Read reverse clutch pressure with output stationary (foot on brake) and throttle opened to achieve 1500 rpm.Reverse and low/reverse clutch pressure should read 165 to 235 psi.If proper line pressure is found in any one test, the pump and pressure regulator are working properly.Low pressure in all positions indicates a defective pump, a clogged filter, or a stuck pressure regulator valve.Clutch circuit leaks are indicated if pressures do not fall within the specified pressure range.If the overdrive clutch pressure is greater than 5 psi in STEP 6 of Test Three, a worn reaction shaft seal ring or a defective solenoid assembly is indicated.If the underdrive clutch pressure is greater than 5 psi in STEP 4 of Test Two-A, a defective solenoid/pressure switch assembly or controller is the cause.Gear Selector PositionActual GearPRESSURE TAPSUnderdrive ClutchOverdrive ClutchReverse ClutchTorque Converter Clutch OffTorque Converter Clutch On2/4 ClutchLow/Reverse ClutchPARK - 0 mph *PARK0-20-50-260-11045-1000-2115-145REVERSE - 0 mph *REVERSE0-20-7165-23550-10035-850-2165-235NEUTRAL - 0 mph *NEUTRAL0-20-50-260-11045-1000-2115-145Low - 20 mph #FIRST110-1450-50-260-11045-1000-2115-145Third - 30 mph #SECOND110-1450-50-260-11045-100115-1450-2Third - 45 mph #DIRECT75-9575-950-260-9045-800-20-2OD - 30 mph #OVERDRIVE0-275-950-260-9045-8075-950-2OD - 50 mph #OVERDRIVE WITH TCC0-275-950-20-560-9575-950-2* Engine Speed at 1500 rpm# CAUTION: Both wheels must be turning at same speed.