May not need to pull trans, you might have dropped the intermediate band strut, you should pull pan and check to see if the band servo and band are intact.
Lon;
You should be able to tell just by trying to tighten up the front band.
The adjuster bolt will just thread right in all the way without the strut or if the band broke.
These transmissions will shift right from 1-3 if the band isn't working, but usually it doesn't take more than the normal RPM's unless there is a fluid pressure leak (like possibly if the band servo or accumulator broke up.)
Screw the band adjuster in and see how far it goes in.
It should normally only screw in about 1 1/2-3 turns and tighten up if the band and strut are in place.
