4L60E, 4L65E, 4L70E

Symptoms:

• Delayed Forward
• Delayed Reverse
• Forward or Low/Reverse clutch distress
• Damaged valve body casting
• Low line pressure upon engagement

Cause:
The OE valve is subjected to high side loading, which wears out the bore and reduces pressure to the clutch.

Correction:
Sonnax Forward and Reverse abuse valve kit is slightly oversized, has extended spool lengths, stabilization flats, annular grooves and a reduced spring load. This valve eliminates clutch pressure loss as well as continued bore wear. One valve and spring work for either the Forward or Reverse abuse location.

In GM 4L60-E, 4L65-E and 4L70-E units, continuous oscillation of the Forward and Reverse abuse valves creates bore wear, allowing clutch feed pressure to exhaust. This reduced clutch pressure causes slippage and burn-up. The Sonnax drop-in replacement valve is slightly oversized and has extended spool lengths to provide additional sealing contact area. The stabilization flats on the inboard end of the spool maintain OE flow, but provide continual valve support while stroking. Annular grooves have been added to prevent side loading and a new spring is provided for the modified valve length. Sonnax Forward and Reverse abuse valve kit 77754-35K fits either the Forward or Reverse abuse location and includes a replacement bore plug.

• Kit raises clutch pressure slightly to prevent slippage and burn-up, an advantage for heavy-duty, plowing or repetitive forward-reverse maneuvers
• Eliminates leakage of clutch feed pressure to the exhaust port at the spring pocket
• One valve and spring combination works for either Forward or Reverse abuse locations
• No reaming is required for the slightly oversized drop-in replacement valve
• Includes replacement abuse bore plug

Contents:

• Valve
• Plug
• Spring

SONNAX Installation Instructions