2000 Chevrolet Silverado 4wheel drive not working

I had new clutch kit replaced (everything) by a very good trans mech.(30yrs exp.) Also went through trans replaced 2nd/4th gear (syncro was bad) 1yr or so before he rebuilt my T-case (all GM parts) and my 4 wheel worked fine before trans rebuild. I talked with him he walked me thru the check list (I'm a 30yr body tech and know mech so not a novice) and everything up to the solenoid works. The light on dash, linkage moves, solenoid clicks and can feel it by hand on, but loaded or not the wheels don't engage. I haven't been able to get with him to look at it, (both of us busy) and just wondered if you can give me an idea before winter and I need it to get around? Idon't see any reason for it not to be working as its rebuilt aswell and was working when clutch went away.