I will start by saying I love Harbor Freight Tools. I bought this Harbor Freight Farm Jack to do some heavy lifting. I will be using this to pull stumps and posts from the ground around the property. This thing has worked like a charm so far. It can pull entire trees up (small ones) if you chose. Of course, it's best to cut the tree to reduce the weight, but it can do it! Great jack for the price.
Seriously, if you need a tool for around the farm, this is a good one to have. Now, I haven't used it on vehicles or tractors, but I see no reason why it would not suffice!