2013 4x4: odd transmission glitch

So:
2013 4x4 DCSB 4.0 auto that does this:
At very slow, downhill right hand turns; like 90 degree stop sign corners, the transmission feels like it freewheels for a minute.
Let off the brakes, give it a little gas pedal, and when you'd expect first or second gear to engage, lock up and take off...
instead, the revs climb for a sec, and nothing much happens.
Not like stomp on the pedal spin it to redline, but, it runs up to 1500-2000 and then kind of slowly decides what gear to slush into.

This seems abnormal.
Could this be "a little low on fluid" causing this?
I don't remember it doing this during the TLCa offroad event I went to.
I don't remember it doing this on road at all before the last month or so.

 

Could be low on fluid and pumping air when downhill does it fall out of gear on sharp turns?

 

No sir. Only slow, downhill right hand turns. Freaky
Behaves normal in all other aspects.

 

Did you check the fluid to rule that out, there's a "how-to" on the site here, all you need is a paper clip, a little WS fluid, 26mm nut and an allen key

 

I haven't. I should. Just wanted to see if anyone knew of a known thing with this symptom set...

 

http://www.tacomaworld.com/forum/2nd-gen-tacomas/63851-how-drain-refill-automatic-transmission.html