Last summer I had this high pitched squeak that would start after I began rolling with the truck in gear (2007 - 4.0 - 4x4), turned out to be the pulley bearings for this motor were under recall (but for the 4runner, not tacoma).
About a week ago a similar squeak has started, at first I thought it was the Ujoint, but I'm worried that it may be the bearings again. It becomes inaudible after about 30mph or 3rd gear, perhaps just the vehicle noise drowning it out. It also increases if I increase pressure on the accelerator peddle.
My local dealer is like 1hr 15min drive so I don't want to just run it up there. I also just hit 70,000 miles and am still under my warranty.