Symptoms:

  • Pin bore wear
  • No 4th
  • Burnt band (GM)
  • 2-3 Bind-up
  • 3-4 Clutch failure

Cause:

Severe case wear at the servo pin bore due to side-loading and high use.

Correction:

Restore proper hydraulic clearance by reconditioning the case bore and installing Sonnax servo pin kit.

4L60, 4L60-E, 4L65-E, 4L70-E

Oversized Servo Pin Kit
Part No. 77787-03K


You need this if... View Instructions Find a Distributor

Sonnax oversized servo pin kit 77787-03K is for use in reconditioned GM 4L60, 4L60-E, 4L65-E and 4L70-E case bores. Matching the longest OE pin length, this chromoly steel servo pin is durable enough for high performance applications as well as stock replacement.

  • Included stiffer 4th apply spring eliminates unwanted band drag in 3rd Gear
  • Added O-ring improves sealing between the pin and 2nd Gear servo
  • Servo pin is fully compatible with OE and aftermarket servos
  • Servo Pin
  • Spring Green
  • O-Ring
  • 4L60, 4L60-E, 4L65-E, 4L70-E Oversized Servo Pin Kit 77787-03K

You need this if...

Vacuum testing at the port(s) indicated fails to hold the recommended minimum in-Hg, or if wear is visually detected.