For 1990-2009 cars

Problem | Action
--- | ---
Low fluid level | Add fluid.
Shift select cable is out of adjustment, binding or damaged | Adjust or replace the shift select cable.
Valve body spacer plate or gaskets not positioned correctly or damaged | Inspect the valve body.
The check balls are omitted or not positioned correctly | Inspect the valve body.
Manual valve binding or sticking | Inspect the valve body.
Manual valve link disconnected | Inspect the manual valve link.
Direct clutch piston or seals leaking or damaged | Inspect the direct clutch piston and seals.
Incorrect line pressure | Perform the Line Pressure Test diagnosis.