Newbe question, Mercury Mountaineer max trailer size

I tow my Jayco SLX 195RB (Approx 3K lbs dry) with an '03 Explorer 4.6L. Using a weight distributing hitch, I've had no issues with stability, and have pulled the trailer in a variety of situations. My combination leaves me wanting for more power in the mountains, but it's definitely manageable if you are reasonable about speed, and accept the fact that the engine will be revving higher during any sort of uphill grade.