Drove my Z to a show last weekend, engaged it on the way
and it responded as it should, parked it inline with the rest of the older cars.
It sat there for 6 hours, so after the show I cranked her up
placed it in gear with no responce, after several tries to engage the rear axle, by engaging and disengaging the Columbia it finally egaged.
I checked for vacum leaks and it was ok.I replaced the seal a few years ago It worked perfectly on the way home.
Any comments please.
Zman

Dont worry just yet,,,
The vac cylinder has to be functional..(test with compressed air if nec)
I always engage mine at low 30-50 and always light load..
remember that vacuum power is greatest after accelerating.First gear is ok..but the torque load in second is less..the momenntum is there, car is rolling a good speed..pull the knob, foot off the gas..press the clutch..ease into 3rd gear..if you floor it it will ratchet in the rear or get stuck inbetween..(like u saw).
I always go easy getting the freeway..I want to safely get on at speed so some times shift from 3rd at about 70..nice and quiet, then oops your doin eighty..I have found the beauty of this car on smooth highway in od to run in the fast lane..
I most always shift 1-2 then od then 3 and kinda get on
highway easy....be carefull when down shifting..you must be moving..i like to as I coast up an on ramp push knob in..declutch shift to neutral..maybe ease back into 3rd to be sure it locked as u stop..
I put synthetic 140 in my columbia after years of fossil 8090..be real sure u fill to the full mark..columbia unit adds fill volume..
If you find yourself in a no move situation again..cycle the switch or rev engine , release throttle let surge of vac kick ..remember to easy and smooth..then go pass lots of cars...

blah blah blah I know...just shift your columbia while moving easy,
cheers...