I just got a 2018 XLT 4WD, and had a 2014 SHO. The Explorer is like a big Taurus, with the same interior layout/button setup etc... I found this thread looking for info on an aux trans cooler. I saw 2 plastic "nuts" in the radiator, which is what we typically used for old school trans cooler installs, so it got me thinking if we really did have one. I can see the engine oil cooler on the front of the engine with the 2 coolant hoses running to it, typical Ford truck/SUV oil to water exchanger. The 4WD XLT w/ Tow Package (52T) does get the 6F55 (Trans Code of "C" on the door sticker).
The parts catalog showed that the Explorers with the 2nd aux trans cooler used a different hose assembly - so if you look by your airbox at the radiator, you would see 2 "T" fittings that send fluid to another cooler. On the non-aux cooler setups, those are just 2 regular hoses. The SHO has the aux cooler mounted at the front lower part of the grille (where a front-mounted intercooler typically gets installed).
The police vehicle brochure indicates that the Police Interceptors have an optional water PTU cooler recommended for vehicles used for EVOC courses or road racing. I've heard rumors about Ford engineers claiming the PTU oil gets cooked due to uneven tire wear (side to side).
Anyhow, the SHO has the 6F55 with 3.5L EcoBoost and the same RDU and PTU as the Explorer Sport, but it's a few hundred pounds lighter. Only the Performance Package SHO and Police Interceptor Sedan gets the liquid PTU cooler, engine oil cooler, and a 2nd aux trans cooler. My SHO didn't have the Performance Package, but I did a lot of datalogging while drag racing and testing it out. The trans fluid does get fairly hot in the summer, about 200F-210F or so, but the Dexron VI /Mercon LV fluid is very thin and is designed to handle this temperature. If the 6F55 in stock form can handle well over 500+ hp / ft-lb in these conditions, it "ought" to be fine for most stock applications.
The PTU is the tricky one. On my SHO, there was no passive duct or liquid cooler. At 20k miles, the 75W-140 gear oil was fairly cooked. I've seen rear differential oil at 100k miles that looked much better than this PTU gear oil. It was overly thick, pitch black, and just full of metal wear / carbon. I've read numerous reports of Police Interceptors WITH the liquid cooler where the axle seals were leaking/blown out due to overheating fluid, some that had to be scraped out. The Mazda CX-9, Ford Edge, Flex, and MKS also share the same PTU (not the Escape or Fusion/Edge) and suffer the same problems. I believe it is due to the proximity of the catalytic converter under the PTU, the constantly spinning PTU, and the low fluid capacity. On the liquid cooled PTUs, there should be a drain plug but the fill port is not there. It has to be filled in via the temp sensor if I recall correctly. On my SHO, there was no drain plug, so I had to siphon it out and then pump fresh fluid back in.
The engine oil cooler has me confused though. I'd think the EcoBoost wants the oil to be further cooled because of the turbochargers as they can get very hot. Maybe because the turbos are also water cooled that they felt the engine oil cooler was only needed on the Police Interceptors and tow packages?
I did numerous UOAs on the show and found that 7000-7500 mile oil change intervals were necessary on the EcoBoost due to Group III-IV synthetic 5W-30s breaking down to a xW-15 or xW-20 at that point, and the TBN getting fairly low. Some theories were floating around regarding cylinder wash down due to the direct injection, but based on my personal UOA results, I'd stick with a 7500 mile oil change interval max regardless of whether it is synthetic, unless using a Group V synthetic that is rated for Extended Performance and even then 10k miles might be stretching it.
