I tow with 4x4 lock off but it feels like in manual mode it always starts out with the rear axle at least partially engaged.
The 3600# trailer pulled surprisingly well, it was a twin axle nice and straight that didn't wag or give me any issues. It had a surge brake that seemed to be in great working condition. A very simple but effective mechanism.
I tell you what, it was not by choice that I ended up pulling that heavy trailer with the Compass. Long story short a deal with a family member and their pickup truck fell through so I had to either make it happen or take a thousand dollar bath. I decided to make it happen and got lucky the trailer was in good condition and not a twisted piece of junk.
Basically just had to pretend I was driving a fully-loaded semi truck. Very slow gradual starts, gentle shifts off the throttle, extra following distance on the highway, keeping close eye on gauges and all that.
Like I said, there is enough gearing with the 9 speed to get a lot of weight rolling. The transmission is plenty tough, they use the same one on V6 engines with way more power. The chassis and suspension is designed well and handles towing better then I would have expected, the rear end didn't even squat too badly which surprised me because it took a jack to get the trailer tongue lifted onto the ball (the trailer was already loaded when I picked it up, and the guy had put the car in the trailer engine first in front of the axles
). I tried to lift the tongue with one other guy and we could barely budge it, that worried me the most but that OEM receiver held up good and the rear springs and shocks shouldered it well. The front end was tipped up a little but thankfully it still steered well, that was only a slight issue when we hit some heavy rain, slight front-end hydroplaning once or twice but the rig drove nice and straight and did not squiggle.
I would not willingly do it again on a long road trip like that, but I don't hesitate to grab a yard of topsoil in my utility trailer from the landscaping place up the road any more or run my brother's big boat to the lake 10 miles away. Its proven tough enough for all those kinds of jobs. I would never try to pull like a 6000 pound bobcat or anything stupid like that, but I don't worry too much when its something like 1 yard of dirt (around 2000 lbs by itself) plus the weight of the trailer, its fine. Slow and careful, low gears and plenty of RPMs and it all rolls right along.