I?ve got a ?85 GMC van (6.2L dsl) that will not lock up the torque converter. Was at cruise speed under minimal load when converter unlocked and hasn?t locked since. Have voltage at trans connector. Solinoid checks ok with air pressure. Transmission doesn?t appear to have vacuum line connected (never has since I?ve owned it) and vacuum pump has been inoperative for a long time anyway. Pan and filter are off now, would like to test further before reassembly. My knowledge of auto transmission repair is somewhat limited but if there are any reasonably simple diagnostic tests that can be performed here, I?m a pretty fast learner. Any help or suggestions would be appreciated.
Thanks