For 1990-2009 cars

Problem | Action
--- | ---
The oil level is low. | Add oil in order to acquire the proper oil level. Refer to Fluid Capacity Specifications .
The external filter is clogged. | Replace the external filter.
The seal ring on the intake tube is leaking or missing. | Install a new seal ring onto the top end of the intake tube. Refer to Allison service manuals.
The main pressure regulator valve spring is weak. | Replace the spring. Refer to Allison service manuals.
The control valve body is leaking. | Replace or rebuild the control valve body assembly. Refer to Allison service manuals.
The valves of the trimmer relays and main pressure regulator are sticking. | Replace or rebuild the valve body assembly. Refer to Allison service manuals.
The input charging pump is worn or damaged. | Replace or rebuild the pump. Refer to Allison service manuals.
The priority valve is missing. | Replace the missing valve. Refer to Allison service manuals.