I have a 2005 4R V6 with 100K on it. In 2018, I purchased a Salem Cruise Lite 201BHXL 24ft dry weight 4233lb dual axle travel trailer.
Upgrades for towing:
#1 - Draw-Tite 75155 Max-Frame Receiver which increased the towing capacity from 5K to 6K or 7300K with WDH.
#2 - Tru-Cool - Max LPD47391 47391 Low Pressure Drop Transmission Oil Cooler
#3 - Andersen Mfg 3350 No Sway Weight Distribution Hitch
#4- AIR LIFT 60809 1000 Series Rear Air Spring Kit with AIR LIFT 25592 Load Controller II On Board Air Compressor System
#5 - Tekonsha 90195 P3 Electronic Brake Control
#6 - Prime Products 30-0104 Clamp-On Tow Mirrors
#7 - BAFX Products 8523900508 for for iOS Devices OBDII Reader
The OBD reader is to monitor trans temp and coolant temp since my 4R has a dummy gauge. If I see the numbers getting too high I can always pull over and let it cool down. Since adding the external trans cooler those temps average 175-185 with 200 max on a steep incline. So far I have towed about 4K miles since I purchased the trailer. After the first few trips my gas mileage was 8-9 mpg. After plenty of research, I added a wind deflector which increased my MPG to 11.5 - 12.5. I know the deflector is ugly and expensive ($350) but increasing my MPG keeps me going longer and eventually will pay for itself.
#8 - ICON 01216 Wind Deflector
I live in TN and purchased the trailer in AL. I towed it from AL back home without the use of the Andersen WDH and I noticed some sway but since adding the WDH I have not seen any sway of any kind. I have yet to drive in high cross winds so I will have to wait and see. I drive in 4 and travel 60 MPH when towing the trailer.
The 4R doesn't like towing up steep inclines and usually drops my speed down to 45-50 mph unless I kick in OD which I rarely do. The only issue that I have to deal with is when passing or being passed by large vehicles (semi's or other travel trailers) which causes a wind vortex which pushes me away or pulls me towards that vehicle. Other than that issue, I am very happy with my 4R towing my travel trailer.