2004r tries but won't complete lockup

[carl creque]

I have a BRF 2004r in a 77 Buick Skyhawk. I did the 4th gear pressure switch lockup wiring but the trans will not go all the way into lockup. It tries and the rpms start to drop but it aborts the process and goes back to unlocked. It will keep trying as long as the trans is in 4th gear and the 12v apply switch in on. Lockup solenoid was replaced at the same time the wiring was done. Verified that the pressure switch was closing using air pressure. Any thoughts as to what might be wrong?

 

[mikestertwo]

Do you have the polarity correct on the solenoid? Remember, there is an internal diode across the solenoid. Do you have the correct pressure switch in the 4th gear line. The stock switch opens when the trans shifts into 4th gear. You need a switch that closes when it sees pressure.