Hi ! My c6 tranny have problem to chift gears and i notice the vacuum hose was fall off i install it and same problem the tranny dont chift gears wird, maybe the modulator is broken? the tranny gears are there but it chifts on a strange way

 

how long has it been since it shifted correctly?

in some cases the governor becomes stuck. It is on the tailshaft inside the case.
my transmission shop said to shift quickly between drive and reverse at high idle with the wheels off the ground to try to un-stick it.
( we ended up pulling the tailshaft housing instead.. wasn't stuck for me)..

I had a valve body problem.

Sam

 

Your engine should have idled much slower after connecting the hose; if not, there's no vacuum to the modulator (plugged or cracked hose)