Chevrolet Repair: 1997 Chevy 3500, chevy 3500, vacuum diagram

Question
When I let off the gas or crest a hill running 50 mph or better, the vehicle shutters.  Almost as if it is unlocking and re-locking the torque converter.  The check engine light does not come on.  I found a disconnected vacuum hose on the passenger side of the engine but can't figure out where it goes.  Could this be causing my problem? Where can I find a vacuum diagram?

Answer
Autozone.com, a free service, has a lot of wire diagrams and troubleshooting tips.
The vacuum hose could go to the transmission, but I think by 97 they quit using modulator valves. But worth a check.
Located on the right side of the tranny case, just above the edge of the pan.

But for sure find a place for that hose, or at least plug it.

Van