2007 Chevy TrailBlazer Transmission Problems

My TrailBlazer is having a major problem.
When I put it into drive the RPMs fly but
the car doesn't even budge. It does the
same in Reverse and 123. I don't feel
anything when I shift and I read that ur
souppose to feel a jolt kinda feeling that
shows it locked in gear. But it's just
smooth shifting with no jolt. We took it to
the auto shop and he changed the trans
fluid and put a new trans filter on and it
worked great for 5 days then it did it all
over again. The transmission fluid was
unbelievably high. So I undid the trans filter
pan and drained a lot out and it's still too
high. I've tried everything and really hoping
it's not a internal problem. Please help if
you can. It would be very appreciated.