Line Pressure Booster Kit
Part No. 4L60E-LB1

Early-style "long" boost sleeve, 1.907" length.

Line pressure booster kit 4L60E-LB1 fits early-style GM 4L60-E, 4L65-E and 4L70-E pumps. Sonnax hydraulic line pressure booster kits contain stronger pressure regulator springs and large ratio boost valves designed to work together to provide progressive pressure increases as driving conditions become more demanding.

Our pressure regulator springs are approximately 10% stronger than OE and more conservative in impact than other aftermarket kit springs. Large ratio boost valves provide higher pressure incrementally and when it is needed the most. The combination of these springs and valves in a Sonnax kit gives you the best of both worlds: a modest pressure increase at the low end, with a high-end pressure that is equal to or greater than that of other aftermarket kit springs.

• Achieve shorter shifts and increased torque capacity without creating low-speed harshness
• Improved band and clutch holding capacity for increased durability
• Progressive pressure increase as driving conditions become more demanding
• All the benefits of increased line pressure without overloading the pump at idle
• Simple and affordable drop-in solution with no special tools or reaming required

Line Pressure Booster Kit
Part No. 4L60E-LB2

Late-style "short" boost sleeve, 1.810" length.

Line pressure booster kit 4L60E-LB2 fits late-style GM 4L60-E, 4L65-E and 4L70-E pumps. Sonnax hydraulic line pressure booster kits contain stronger pressure regulator springs and large ratio boost valves designed to work together to provide progressive pressure increases as driving conditions become more demanding.

Our pressure regulator springs are approximately 10% stronger than OE and more conservative in impact than other aftermarket kit springs. Large ratio boost valves provide higher pressure incrementally and when it is needed the most. The combination of these springs and valves in a Sonnax kit gives you the best of both worlds: a modest pressure increase at the low end, with a high-end pressure that is equal to or greater than that of other aftermarket kit springs.

• Achieve shorter shifts and increased torque capacity without creating low-speed harshness
• Improved band and clutch holding capacity for increased durability
• Progressive pressure increase as driving conditions become more demanding
• All the benefits of increased line pressure without overloading the pump at idle
• Simple and affordable drop-in solution with no special tools or reaming required

Line Pressure Booster Kit
Part No. 700R4-LB1

Line pressure booster kit 700R4-LB1 fits GM 4L60 (700-R4) and 200-4R transmissions. Sonnax hydraulic line pressure booster kits contain stronger pressure regulator springs and large ratio boost valves designed to work together to provide progressive pressure increases as driving conditions become more demanding.

Our pressure regulator springs are approximately 10% stronger than OE and more conservative in impact than other aftermarket kit springs. Large ratio boost valves provide higher pressure incrementally and when it is needed the most. The combination of these springs and valves in a Sonnax kit gives you the best of both worlds: a modest pressure increase at the low end, with a high-end pressure that is equal to or greater than that of other aftermarket kit springs.

• Achieve shorter shifts and increased torque capacity without creating low-speed harshness
• Improved band and clutch holding capacity for increased durability
• Progressive pressure increase as driving conditions become more demanding
• All the benefits of increased line pressure without overloading the pump at idle
• Simple and affordable drop-in solution with no special tools or reaming required

Forward & Reverse Abuse Bore Plug

Fits in either of two locations

The bore plug in 4L60-E units is held loosely in place with a coiled spring pin, allowing the opposing spring and oil pressure forces to stroke it within the bore. This constant oscillation causes the plug to wear and allows PR oil at the low overrun valve and 3-4 clutch oil at the 3-2 downshift valve to exhaust at the abuse valves. This excessive oil loss can result in delayed apply of the low/reverse clutch and a tie-up of the 3-4 clutch and 2-4 band.

This plug is used in two locations in the valve body: to separate the forward abuse and low overrun valves, and to separate the reverse abuse and 3-2 downshift valves.

Oversized Pressure Regulator Valve

Part No. 77917-06

A worn OE pressure regulator valve can be detected in two ways. The first is a dynamometer test that reveals low line pressure during boost conditions (look for 50-100 psi less than specified in Reverse). The second is vehicle symptoms such as clutch slippage, reverse chatter and 3-4 clutch failure. Any of the above problems indicate bore wear that should be addressed.

To address pressure regulator leakage in GM 4L60, 200-4R pump covers, Sonnax offers oversized pressure regulator valve 77917-06. The Sonnax valve permits pump covers to be restored to OE specifications by correcting for wear and leakage at the pressure regulator valve.

• Refurbish the pump cover by reaming the bore and installing an oversized pressure regulator valve
• The pressure regulator valve helps restore control over the pressure regulating circuit by eliminating leakage

Oversized Pressure Regulator Valve

Part No. 77917-07

A worn OE pressure regulator valve can be detected in two ways. The first is a dynamometer test that reveals low line pressure during boost conditions (look for 50-100 psi less than specified in Reverse). The second is vehicle symptoms such as clutch slippage, reverse chatter and 3-4 clutch failure. Any of the above problems indicate bore wear that should be addressed.

To address pressure regulator leakage in GM 4L60-E, 4L65-E and 4L70-E pump bodies, Sonnax offers oversized pressure regulator valve 77917-07. The Sonnax valve permits pump covers to be restored to OE specifications by correcting for wear and leakage at the pressure regulator valve.

• Refurbish the pump cover by reaming the bore and installing an oversized pressure regulator valve

• The pressure regulator valve helps restore control over the pressure regulating circuit by eliminating leakage