Yes! I had this exact same issue on my 06 Suburban with the automatic control. Replaced the blower motor resistor (the only one that seemed to be a direct "plug and play" was from Amazon) and motor from RockAuto. I thought it was the motor, until I swapped another known good motor and same thumping sound! It sounds like something is loose or something like that.
I went back and the Amazon one and some reviews were saying this. I found a Four Seasons blower motor resistor that worked, I just had to cut off the old connector and splice the new one, but the instructions were very clear.
Problem solved!
I can provide part numbers if you want. The Amazon one was like $30-ish IIRC. No real name brand, made in China.
The Four Seasons was like $90 from RockAuto, assembled in the USA.
Got it, I’ll try another resistor
ive taken the motor out of the mount and held it in my hand , and it still has the knocking, coming from the connector that attaches
it’s almost like the other side of the plug is interfering with the motor
edit, after some more research, the blower might be bad too, as the new resistor did Seem to open and even higher fan speed, but shortly after, went back to what I had been used to and didn’t have the higher speed