Originally Posted by Johnt43
I have a 2007 Tacoma 4.0 V6 w/o the tow pkg. It has a 5000# hitch.
The hitch is fine, but the ratings of the truck are more important. That information is in the owner's manual. I don't have a 2007 Tacoma manual handy, but the 2008 manual stays that without the towing package, the maximum trailer weight is only 3500 pounds; it would be 6500 pounds with the package. There are other limits, such as Gross Vehicle Weight Rating (GVWR) and Gross Combination Weight Rating (GCWR), to consider as well; in this case, to avoid exceeding the GCWR all of the weight that you carry in the truck (of passenger or cargo) reduces the trailer weight limit by the same amount.
The lower GCWR and trailer weight limits are due to powertrain (engine and transmission) reliability concerns when pulling a heavy load without the equipment included in the towing preparation package (likely a transmission cooler and perhaps other parts). So it's not a question of stability or control, or even of performance, but of reliable operation.
The truck is big and powerful enough, but without the towing preparation package, it isn't properly equipped to handle the work reliably.