I've been searching the forums and the interwebs for a bit trying to figure out this issue and if its an in-car fix or if the Doug Nash unit needs to be pulled and fully rebuilt.
Issue: When the overdrive unit gets power there is no change in gear ratios or engine RPM Except when I let off the accelerator. Example: running in 4th gear at 60 mph, push in clutch, power to the overdrive unit, let out clutch. no change in engine rpm or gear ratio. However when i let off the throttle to the unit does engage and the rpms drop significantly to where they would be with full engagment. This happens in every gear (I havent tried it in first gear because I don't forsee me ever using overdrive in 1st gear)

1986 corvette z51
Converted to Carb style setup (holley Sniper) meaning no ECM control. In fact the ECM isnt even in the car anymore. Overdrive is wired direct to a toggle switch which applies 12 volts to the unit when I flip the switch.
I have dropped the pan on the OD. changed the filter and fluid. Refilled to proper level etc. There were no parts or massive buildup of clutch material around the magnet when I changed the filter and fluid. (changed the fluid in the BW t-10 at the same time.

Scratching my head here on this one. Hoping for simple(ish) fix on this one for the time being.

Of course the eventual plan is to put in a Tremec TKX 5 speed when the finances allow for that.