Inspect the condition and level of your automatic transmission fluid. If the clunking happens consistently between 2 and 3 only, it's most likely a trans issue.
More likely, if the clunking happens when speeding up or slowing down through all the gears but is only most noteable between 2 and 3, you have an issuse outuse the transmission, with universal joints, constant-velocity joints or engine or transmission mounts.
Answers
More likely, if the clunking happens when speeding up or slowing down through all the gears but is only most noteable between 2 and 3, you have an issuse outuse the transmission, with universal joints, constant-velocity joints or engine or transmission mounts.