Low Main Line Pressure in All Ranges

WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet 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 Check .
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 (PCS1 and PCS2) or Control Valve Solenoid Replacement (SS1, SS2, SS3, TCC, and MAIN MOD) .
Main pressure regulator valve spring weak, broken, or missing	Inspect the spring and replace, if necessary.
Control module body leakage - separator plate not flat, 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.