What causes my AWD Journey to make a clunking noise when I put it in reverse? on 2010 Dodge Journey

It also does it when I shift into drive.The rear differential was replaced a few months ago and an update was done on the transmission because there was a clunk in the front as well. This was a temporary fix because it's doing it again.This is the third time we have had it at the dealer. The last time, they told us that it is in the normal range.

Asked by for the 2010 Dodge Journey
Go back to the dealer and complain, if they repaired for free the first time, then they know that it is an issue. Just tell them that you are not satisfied and you are considering applying for the Lemon Law because you have had 3 repair attempts for the same complaint. That will get their blood pumping.
As for what it is, there is too much slack in the gear train. It could be in the transmission, the transfer case or one or both of the differentials.