GM 4T65-E Channel Plate Common Problems & Solutions

Valve Body Xpress

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Common Problems that occur with 4T65-E Channel Plates:

  • Worn actuator feed limit valve (AFL) bore
  • Pitted, damaged or noisy axle bearing
  • Worn or damaged pump shaft sleeve
  • Channel plate to case gasket blowout


Actuator Feed Limit Valve Theory

The AFL valve is a regulating valve that controls line pressure to a maximum of 115 lbs. AFL regulated oil goes to the EPC solenoid and the 1-2/3-4 shift solenoid. When the AFL bore wears, regulated pressure leaks to exhaust, which lowers the pressure and volume of oil to the solenoids.

A worn Actuator Feed Limit Valve Bore can cause:

  • Low line rise and can set a P1811 code, shift adapts at maximum
  • TCC slip due to low line rise, setting a P0741 TCC slip code
  • 2nd gear starts
  • Falling out of 4th gear


Solution

  1. Flat sand both sides of the channel plate to fix gasket blowout.
  2. Ream AFL bore and install new oversize AFL valve and springs to restore the hydraulic integrity of the AFL valve circuit.
  3. Inspect the axle bearing and replace as needed.
  4. Install a new axle seal.
  5. Press in a new sleeve.
Related Part(s)
Related Unit(s)
Subject(s) Included
  • General Diagnostics and Theory

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