There aren't any "known problems" or common problems on either engine, they are both rock solid.

On my 2.7L w/ 5-spd, I have averaged 22.85mpg since I got it, with a high of 27mpg on a highway road trip.

My neighbor tows a 12ft HD steel trailer with quads up and down the small hills of eastern Ohio w/ his 2.7L w/o any problems, it goes just as well as unloaded.

The Taco rear leaf springs are quite soft, a yard and a half of dirt has mine sitting on the bumpstops. This can be remedied easily enough.

No limited slips from the factory, sorry. Some do have the factory electric locker option, which is very desireable.