A/T - 440T4 No Second Clutch Switch
BULLETIN: # 103TRANSMISSION: 440T4
SUBJECT: No second clutch switch operation
APPLICATION: GM
Beginning in 1988, some 440-T4's used a 2nd clutch signal switch in the pump (Figure 1) to inform the ECM that the transaxle has upshifted to 2nd.
A hole in the valve body in the location shown (Figure 2) is required to feed 2nd gear oil to the switch.
If an exchange valve body, without the hole, is installed on a unit which has a 2nd clutch switch, the result will be no 2nd clutch switch operation, since no oil will be fed to the switch.
A valve body which does not have the hole may be modified by carefully drilling a 1/8" hole as shown in Figure 2. Be sure to thoroughly clean out the chips after drilling.