Tow vehicle is a 2009 Ford Expedition EB 4 wheel drive 5.4 with factory tow package and "tow- haul" selector switch- this is 4th one we have had going back into late '90s.
These are rated to pull better than 8000 lbs with tongue weight of 600 lbs max.
Boat is a 235 Mako with total towed weight of 3300 lbs plus trailer - trailer dual axle aluminum. Tongue weight is right at 600 lbs.
I have pulled this boat with 2004 and 2003 Expeditions with no issues.
The 2009 has a sway in the SUV (not the boat) with tow/haul turned off - it reduces with tow haul turned on but is still there. Tires are LT with 45 psi.
Any ideas on cause of sway? <!-- / message -->

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