Random rpm surge then drop

[Harley McIntyre]

Was driving to work, and while I was accelerating to 60, around 50-55 the rpm jumped to 3k really fast then back down just as fast to around 1850-2k as usual. I wasn't accelerating hard at all, nor did I put any extra throttle input in. There's no way it could have shifted that fast without me feeling it. I didn't notice a jolt either. Anybody know what could be going on?
I have the 4.6l

 

[D Hook]

I've had that happen when accidently hitting the O/D button while reaching for the AC controls. Didn't feel the jolt either, looked down at the tach and it was at 3K. Also had it happen when I first bought the vehicle but didn't hit the O/D button. Just downshifted on it's own on the highway, then upshifted. (On level grade, no hill.) Took it in and got the transmission fluid changed (not flushed) and it's never done it since.

 

[Harley McIntyre]

I took it into Ford for a pcm/tcm update, but they pulled the "we can't replicate the problem" bull. You'd think if you're willing to pay they would just do it lol. it felt like I was more knowledgeable than the service department was. I'm assuming that's what's causing it. I have the bump issues too.