Sonnax 77754-21 Forward and Reverse Abuse Bore Plug for GM 4L60E 4L65E 4L70E Transmissions

The bore plug in GM 4L60-E, 4L65-E and 4L70-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.

Key Features:

• Increased diameter to restore proper valve body clearance in the circuits
• Drop-in design with no tools required for installation
• Prevents valuable oil pressure loss at critical valve circuits
• Sold individually

Resolves These Problems:

• Delayed reverse engagement
• Burned 3-4 clutch and bind-up
• Burnt low/reverse clutch
• Burned 2-4 band

This Sonnax forward and reverse abuse bore plug is an essential upgrade component for rebuilding GM 4L60-E, 4L65-E, and 4L70-E automatic transmissions to restore proper hydraulic function and prevent transmission failure.