Denulya

Hey Yall, first time posting. TIA for your insight. I just bought a 2014 silverado 1500 with the 4.3 engine. Just crossed 100k on the odometer, I’m having some shuddering like I’m driving over drunk bumps at low RPMs. Seems to be happening a bit more every week. I replaced my spark plugs and wires, dropped my pan and found ZERO metal shavings on my magnet. I replaced the transmission oil, threw on a hose on the pump and cycled about 7 extra quarts through the transmission. Still have the shudder. I don’t know transmissions well, what would you say my issue is? Torque converter? Thanks for your help!