I am having a similar problem with my 2004 durango. Drivea and shifts fine when i bought it. Month later driving on highway heard a pop or bump and shifted down to 3rd and wouldnt fo back into OD. Turn car off and back on no problem. Now happening more often. At stop light put it into 1st starts in 2nd. Put int into 2nd and starts in 2nd. Start in 2nd and around 3000rpm shift in D. Will not shift into OD. Anyone else with this problem. Has to be computer related giving you can reset the tcm for short periods of time to hold you over. Im thinking shift selonoid or stuip sensor. Any knowledge would be greatly appreciated.