OK so after extensive reading I've seen a lot of the same info on using compressed air to check clutch engagement is this true and what would be the chances of that being z good indicator saying my trans will work after the rebuild
DO IT !!! By all means AIR CHECK it. Follow whatever instructions you're finding on how to do it, and DO IT. DO ALL DRUMS AND CLUTCHES just like the directions say to do. What air check ensures, is that you did not tear any lip seals to the clutch pistons and when fluid gets behinds the piston and the seals that seal them into drum that the piston WILL compress the clutch pack and it work just like it's supposed to. IF it does not, then you've already ruled out bad seals or piston in a clutch pack and that the problem if there is one, is somewhere else, like a check ball forgotten, a hung valve in the VB.
In an air test what you want is, to hear, see and/or feel the clutch pack compress and NO AIR LEAKING into the drum, like a hissing noise. If you hear a hissing noise, then you tore a lip seal and need to pull it apart again and replace the torn seal with a new one.
After you've done several transmisisons you may not air test every drum, or just the one that you might have question about, but normally you'll get good enough to trust your work and KNOW you didn't tear seals. You can tell by rotating the piston in the drum before you put the return springs on and the retainer and snap ring. If it's not smooth or you feel it snagging, then safe to assume you tore a seal. BUT to answer your question, YES, By all means, being a rookie for surem AIR test it. You don't to blow seals either, so maybe use 30-40lbs strength.
