It is the lock-up solenoid and not shift solenoid.
To check solenoid seals, remove suspect solenoid. Connect battery voltage to solenoid. Apply 71 psi (5 kg/cm2 ) to solenoid with battery voltage connected. With battery voltage applied, air should pass through solenoid. Disconnect voltage to solenoid. Ensure air does not pass through solenoid. Replace solenoid if defective.
Images (Click to enlarge)
Saturday, March 12th, 2011 AT 7:17 PM