Wirelessly posted (BlackBerry7130e/4.1.0 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/104)

Traveling from T3 to T4, the OUTER track AirTrain (bound for either Jamaica or Howard Beach stations) is the one to take. T4 is the next stop on these trains. (The outer- track trains serve the terminals in ASCENDING numerical order from T1 to T8/9 before heading to Jamaica or Howard Beach; the inner-track trains serve the terminals in DESCENDING numerical order from T8/9 to T1 and then travel from T1 to T8/9 to start the loop anew.) I'm sure it's possible to walk from T3 to T4; I'm not sure that I would recommend it, though, especially with the availability of a free AirTrain.

As to Autolink, you'll have to check with their carrier to see if it's available to them. I thought it was only available to the disabled. (And it might not be any faster than AirTrain anyway,)