Yes, don't do this. Get yourself an older pickup (F150, 1500). It might not be pretty but spending $1500 on a truck is better than having to replace your transmission in your Equinox. The equinox has a V6, that doesn't have the same output as a straight 6 cylinder would, plus like the other ladies mentioned, the braking ability. If you have the typical two horse steel trailer, that's a pretty heavy trailer even though it may not feel like it when you're towing it. You would easily be at capacity with your horse in there. Besides, you can just throw things like a bale of hay in the box of a truck.