Which is NOT a function of the main pressure regulator valve?

Which is NOT a function of the main pressure regulator valve?

• A. It feeds the converter-in circuit.
• B. It dumps excess pressure to the pump's inlet side or to the sump when operating pressure is reached.
• C. It directs oil from the converter out circuit to sump.
• D. It indirectly feeds the transmissions lube circuits.

Answer: (C)

The main idea here is how the main pressure regulator valve controls hydraulic pressure and where that pressure is routed in the transmission. This valve maintains the system pressure by sensing the overall pressure and modulating flow to keep it within the desired range. It supplies the converter-in circuit, providing the regulated pressure needed to engage and operate the torque converter as part of normal transmission function. When pressure rises beyond the set point, the regulator valve dumps the excess back to the pump inlet side or into the sump, which prevents over-pressurization and protects components. That regulated pressure also supports the lubrication system, indirectly feeding the transmission’s lube circuits so they receive adequate pressure as the system operates. However, directing oil from the converter out circuit to the sump isn’t a function of this valve. The converter-out path is managed by other pathways and valves in the system, not by the main pressure regulator valve.

The main idea here is how the main pressure regulator valve controls hydraulic pressure and where that pressure is routed in the transmission. This valve maintains the system pressure by sensing the overall pressure and modulating flow to keep it within the desired range. It supplies the converter-in circuit, providing the regulated pressure needed to engage and operate the torque converter as part of normal transmission function. When pressure rises beyond the set point, the regulator valve dumps the excess back to the pump inlet side or into the sump, which prevents over-pressurization and protects components.

That regulated pressure also supports the lubrication system, indirectly feeding the transmission’s lube circuits so they receive adequate pressure as the system operates. However, directing oil from the converter out circuit to the sump isn’t a function of this valve. The converter-out path is managed by other pathways and valves in the system, not by the main pressure regulator valve.