Originally Posted by swingaling

If you have checked bags, then it's 100% not possible because they won't through check.

Without checked bags, it takes 10-15min to clear immigration and customs (with GE and assuming no delays). Then get to the tram and wait up to 5min for it to arrive, followed by a 5min tram ride to T3. Then get yourself to departures and go through security, which will take 10-15min (or more) even with Pre-Check. And finally walking/running to your gate, taking another 5-10min+ depending.

So at a minimum it will take 30-40min to get to the onward flight, but it could easily take 60-70min+. Ultimately your call, but I wouldn't attempt that connection.

FWIW, I just flew into T5 last week on AA flying J. It took me a solid 30-40min to get to T3 -- with GE, Pre-Check and no checked bags.