Well in your case the engine/trans info is actually better. I don't have a clue what is inside that vehicle but I do know that trans has its vacuum modulator at the right rear of the trans. It should have manifold vacuum on it and will shift real hard if it does not.
If left with no diagram, I would make sure I had no vacuum leaks and approach each system by function. That motor will have vacuum to these possible areas. Dist timing, warm-up regulator mixture control, possible decel dump valve, maybe EGR, etc.
Bosch Master, ASE Master, L1
33 years MB technician