DEFINITION: No fourth gear to third gear downshift

External Automatic Transmission Control Valve Body Assembly (39)

Verify that all solenoids respond electrically. If there is no response, perform an electrical diagnosis. If there are no electrical concerns, remove the solenoid valve assemblies as needed, and inspect the solenoid O-ring seals, and the solenoid bores for signs of damage and/or missing seals. If the solenoid valves responded electrically and there are no bore or seal concerns, replace the solenoid valve assemblies as necessary due to possible internal mechanical concerns and retest. If a condition is still present after replacing the solenoid valve assembly, replace the complete automatic transmission control valve body assembly (39).

Internal Automatic Transmission Control Valve Body Assembly (39)

Remove the automatic transmission control valve body assembly (39) and inspect the items listed. Inspect the internal bores and the valves for signs of wear and/or damage, including internal contamination. If unable to verify any repairable concerns, replace the complete automatic transmission control valve body assembly (39).

Clutch - Mechanical/Hydraulic

4-5 Clutch Assembly (15)

Inspect the 3rd gear band servo piston assembly (57) for signs of internal binding, internal contamination, and/or missing parts. If the servo assembly was found to be binding in the transmission case bore, it is possible that there is damage to the 3rd gear band assembly (16). The 3rd gear band assembly (16) should be physically inspected to verify proper operation.