Diagnostic Procedure

Check the hydraulic pressure. See HYDRAULIC PRESSURE TESTS under PERFORMANCE TESTS. Measure the hydraulic pressure of each element when the transmission is in 1st, 2nd or reverse. Check if each hydraulic pressure is within the standard value. If some elements are within the standard value and some are not, recheck the symptom. Are all hydraulic pressures within the standard value? If so, go to step 3 . If not, go to next step.
Adjust line pressure. See HYDRAULIC PRESSURE ADJUSTMENTS under PERFORMANCE TESTS. Then check the symptom. Is the symptom eliminated? If so, diagnosis is complete. If not, go to next step.
Check when shift shock occurs. When does the shift shock occur? If shift shock occurs when engaging from Neutral to Drive and Neutral to Reverse, go to next step. If shift shock occurs when the vehicle starts moving, go to step 5 .
Remove the transmission. Replace the oil pump (oil pump cannot be repaired). See appropriate OVERHAUL article. Check the symptom. Is the symptom eliminated? If so, diagnosis is complete. If not, go to step 6 .
Disassemble and clean the valve body. See appropriate OVERHAUL article. Check the "O" ring installation, bolts for looseness and valves and valve body for damage. Repair or replace the faulty parts. Is the repair possible and the symptom eliminated? If so, diagnosis is complete. If not, replace the valve body assembly. Check the symptom. If symptom is not eliminated, go to next step.
Possible faulty PCM exists. Replace the PCM if necessary. See POWERTRAIN CONTROL MODULE under REMOVAL & INSTALLATION. Is the symptom eliminated? If so, diagnosis is complete. If not, go to step 1 .