So lately I've been noticing some shudder AFTER shifting gears. No slipping or any other tranny warning signs.
Did some searching, but couldn't find anything real concrete.
It's very intermittent with no conditions apparent making it happen or not happen.
Tranny was rebuilt about a year ago, roughly 10k miles on it.
Going to be doing a 3x2 for now, and a third drain and refill sometime in the near future.
I'm almost certain it's the torque converter, but is there anyway to confirm this?

 

Hey man .... I feel your pain !
With only 10k on a freshly rebuilt tranny, I'd be going back to who done the rebuild. Was there any type of warranty ? Man o man, only a year and acting strange !!! Hmmmm......!

Have ya checked all the mounts ? How does the fluid appear ? Does it seem more frequent when warm or cold ? Worse in the lower gear shifts ? BUMMER !!!

 

It's definitely not the mounts. Fluid looks like new.
It doesn't seem to be temp related, it's done it cold and hot.
It's most noticeable in 3rd and 4th gear, but happens in 2nd gear as well.
In SS, I can hold it in a gear, play with giving it some gas and coasting, and it'll happen, so it doesn't seem to be related to shifting of gears, but the Torque converter lockup.

 

It sounds like torque converter lock up shudder. The cheapest, fastest, easiest, thing to do would be adding a bottle of Lubegard's dr.tranny instant shudder fixx. If you can't find it at an auto supply, a good transmission shop should have it. To find a good trans shop, start by eliminating any of the chain/franchise operations.