I have a 2014 Tacoma 4WD, 4-door TRD that I like very much. 80,000 miles and more importantly, it's paid off.

A few weeks ago the steering got really tight during a 3 hour trip while I was towing a boat. The belt appears fine and there was no squealing or screeching, just tightness in the steering and it seemed "grabby" for lack of a better word.
Initially I replaced the power steering fluid after my guy told me that sometimes that actually relieves a power steering issue. No go, might have helped minimally, but it didn't fix the issue. At this point I replaced the power steering pump. It was probably in my head, but I thought that the problem might have resolved a tiny bit, but my wife drove the truck and confirmed that the steering was still awful, so I took it back to the shop. This time he lubed the U-joint in the rack or wherever that may be. It seemed to make the steering smoother, but it still seems tight to me. I can drive the family Avalon with one finger on the wheel and I seem to think that's how the truck (or any power steering unit) should operate, but mine still seems tight, smooth, probably not dangerous, but still tight.
I'm at the point where I have a good bit of equity in the truck and it wouldn't break my heart to trade it on a new unit, but I don't want to do so for the wrong reasons, nor do I want to give someone else my problem. The truck is otherwise like brand new and I'd just as soon fix the issue and keep the truck.
Any ideas? Is this a common issue in the Tacoma? What should I do to trouble shoot the issue or what should I have my mechanic check?