My 89 Gen 1 Montero has sit idle (started up occasionally) for a couple years. Recently I started driving it again. It will not engage the overdrive (OD) clutch. The OD was working fine before it was parked.

I removed the OD solenoid and applied 12v current and I get a definite click from the solenoid. From my research this indicates that the solenoid is functional.

What other adjustments or electrical issues could be causing the truck to fail engaging the OD?

Thanks for your input !