Are you having trouble finding the root cause of code P1811, low line pressure, converter clutch slippage and/or 2nd gear starts? A worn actuator feed limit (AFL) valve bore in the channel plate can cause these problems. The OEM AFL valve is made of steel and almost never looks damaged. Typically, the AFL valve bore wears and allows the AFL oil to leak to exhaust. Our extensive research has concluded that even low mileage units have excessively worn AFL valve bores. The AFL valve regulates line pressure to a maximum of 115 PSI to feed the EPC solenoid and the 1-2/3-4 shift solenoid. When land "C" leaks (see Figure 1), AFL oil leaks to exhaust and leave little or no oil to operate the EPC solenoid and the 1-2/3-4 shift solenoid. When lands "A" or "B" leak, the AFL valve cannot regulate itself and allows full line pressure to the EPC solenoid and 1-2/3-4 shift solenoid.

The AFL valve bore can be checked for wear in two ways.

1. Remove the retainer, spring and AFL valve, clean the valve train and channel plate and install just the AFL valve in the bore. Place a flashlight on the worm tracks above land "C" and look for light between the bore and the valve (see Figure 2). If you see light it is worn!
2. With the AFL valve, spring, and retainer installed in the channel plate, squirt some ATF into the cup plug. Blow air into the cup plug and if you see leaks at land "A" of "B" the bore is leaking. The AFL valve should move against the spring when air pressure is put into the cup plug. If shop air will not move the AFL valve when wet with ATF it will not be regulating in the vehicle.

Call 866-2GET-VBX