2010 low speed shudder at 20-30 miles per hour.

Wondering what could be causing this?

 

Can you describe it more? My 5.7l '07 has shudder when the toque converter locks and unlocks. I put 2 tubes of Shudder Fixx in the transmission and it's almost 100% gone.

 

Also if you have access to a tuner or HPT tuner you can remove flex lock from the torque converter. It creates excess heat. It partially locks torque converter at lower rpms before fully locking. I've removed mine for the past 6 months.
Shudder fixed is a decent additive. I had a mild shudder and p2757 off and on over the years. I top off a drain and fill will an extra 1/2 quart of WS atf. Hasn't been back in over a year.