Help me diagnose

So I have had my Ex a little more than a week and everything seems fine. 180k 4x4 v10. Transmission is a little clunky when downshifting into first but I have yet to get to flush the tranny yet. I picked up a used 8x20 ft enclosed car hauler today and it was towing like a champ no issues running along at 65-70 I did remember to turn off OD as it seemed a little confused at first. RPMS were around 2-3 with the 3.73s but all the gauges looked good no weird sounds no issues. Right as I was pulling into my neighborhood I stopped at a signal and saw a somewhat largeish puff of white smoke behind the vehicle. At first I thought it was I locked up one of the trailer tires or something. When I made another left into residential side street I again saw it but saw some seemingly coming from the hood. When I pulled over in my neighborhood and parked I could see some vapors coming from under the hood but it quickly stopped, nothing leaking under the rig. I let it cool a little checked the oil etc and everything seems fine.

Again all gauges were reading great on the drive. I let the rig run for about 30 minutes, tried revving it a bit, put it in gear for a while etc and no sign of any issue.

The only "clue" that might tell me something was it looked like the top of the battery had some wetness residue on it, and there was some water just a few drops on the passenger side back by the firewall on what I think is the brakebooster. I need to get the trailer out of my HOA loving subdivision and over to the storage spot now that I loaded my track car into it but I don't want to injure my rig and want to make sure it's ready for towing.

Thoughts?

It did seem like the radiator might be a little overfull? I will check it again tomorrow when it has cooled down? Could it have vented without overheating and caused the smoke from stuff hitting hot engine?

Brake booster probably isn't on the passenger side. Most Fords have HVAC stuff in that area. I know that Rangers have a "heater control valve" in that area that can cause similar issues. It's a vacuum controlled valve that controls coolant flow through the heater core. Its made from cheap plastic and usually springs a leak that drops coolant onto the manifold.

I just know it was a "round" looking thing against the firewall. could it have been something that happens under braking which is why it happened then? It is true that is the side where I needed to recharge the AC the AC is still blowing cold like a champ after this

In reply to Jaynen :

Yeah. That’s the HVAC side. I’d suspect something happening over there. 

Passenger side has hvac stuff like blower motor, evaporator, accumulator, ac and heater hoses etc all in a clump of black plastic. Which side is your battery on? What's your coolant level look like?

Battery on passenger side, coolant level to me looked almost too high yesterday. Apparently on the EX forums they suggest something like this can happen under heavy towing from a front trans seal overheat leak

Coolant level yesterday when hot was over the "max" fill

This is what had fluid on it but I can see all those metal pipes are AC and get condensation so I don't think it had anything to do with it

It looks to me like the trans might be a little overfull? which could maybe contribute to leaking from a seal when hot?

That's your HVAC fan on the passenger side.

AC evaporator drain tube, split/ hole/clogged?  After running a while, with AC on you should see some water under the truck, from draining, generally.

Does it puff any smoke on cold start up?

This is the trans I think the trans pan is just behind it. So maybe it was trans fluid leaking out when hot while towing. It was 95 and humid here yesterday but it was not mountainous and at the time the car hauler was unloaded

Well, generally whiteish smoke is either just water steam, or burning coolant. Given that you haven't lost any coolant, that leaves steam. Condensation from AC lines slowly dripping onto an exhaust manifold wouldn't make enough steam to be visible while driving.  Unless perhaps the evaporator drain is clogged and you have a large amount of water sloshing around the bottom of the evaporator case and then escaping through a seam in the box when you take a turn and hitting the manifold. I guess i second  checking that your ac condensate water is actually hitting the ground.

EDIT because i saw you posted while i was posting.  Burning ATF does leave a whiteish smoke so this is a possibility. If it's coming from the bellhousing it's probably the converter seal. If its running down the case from somewhere on top it's probably coming from one of the vents in which case further diagnosis is necessary.

The excursion board guys said something about a front seal (maybe the converter) that can leak when overheated. I noticed a bit of slow shifting if you will or slipping when going into overdrive (all other gears and comes out fine)