Low Main Line Pressure in All Ranges

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Condition	Action
Incorrect fluid level	Correct the fluid level. Refer to Transmission Fluid Checking Procedure .
Plugged or faulty suction filter	Clean or replace the oil suction filter element. Refer to Oil Pan Replacement .
Main pressure regulator valve sticking	Overhaul the control module assembly.
Leaking solenoids in control valve body assembly	Replace the solenoids. Refer to Control Valve Solenoid Replacement (Solenoid A, B) or Control Valve Solenoid Replacement (Solenoid C, D, E, F, G) .
Main pressure regulator valve spring weak, broken, or missing	Inspect the spring and replace if necessary.
Control module body leakage - separator plate not flat, separator plate gasket leakage, loose control valve body bolts	Replace or rebuild the control module assembly. Care should be taken when removing and labeling shift springs.
Faulty or incorrect fluid pressure gage	Repair or replace the gage.
Oil pump worn or damaged	Replace or rebuild the oil pump.
Leak in suction circuit	Inspect the suction circuit for leaking seal, gasket, or mating surface.