I noticed the transmission down shifted early when I was coming to a stop and I heard a noise on the left side of the van.I went about 5 blocks, stop to make a turn and it wouldn't move. I went thru all the gears and it still wouldn't move, so I cut it off and back on and it finally snap into gear hard I made my turn. I got back in it 15 minutes later and it took off like normal I made it about 4 blocks and it did the same thing again. I did what I did before and it went another 6 blocks and did the same thing but wouldn't move no more so I had it towed home. It acts like something is holding it back when I put it in gear to move. It never went into limp mode during all this. When I use the windshield wipers it goes into limp mode. The service engine soon light was on also. The guy at Auto Zone said the code was p1768.