GM 4T65-E Channel Plate Common Problems & Solutions
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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
- Flat sand both sides of the channel plate to fix gasket blowout.
- Ream AFL bore and install new oversize AFL valve and springs to restore the hydraulic integrity of the AFL valve circuit.
- Inspect the axle bearing and replace as needed.
- Install a new axle seal.
- Press in a new sleeve.
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