I installed a new American Standard toilet that can flush a zillion golf balls, but when flushed, the tub drain gurgles from the pressure in the 'P' trap. How can I stop that?

Can you tell if its trying to push air out or suck air in?

I believe it is a 'push out' situation. There is a 1 1/2 in. vent pipe attached to the sink/toilet/tub piping , but the attachment is higher than the tub 'P' trap. Maybe I should run a snake down it, ensure it is clear?

If it looks like its pushing out then you probably do have a vent issue. The vent is clogged most likely. If its sucking in then its still a vent issue but you can install a air admittance valve under the sink to solve that problem. You can try snaking the vent to see if something is clogged.

Thanks, Adam: will try it. Crippled old guy up on the roof in 10 degree air: brrr... Better have the wife with vidcam for AFV.