I know this is not a Buick, but there are some very smart guys here that I think may be able to help. My friend has a 1996 Dodge Grand Caravan 3.3 liter. Here are the symptons. He can get in the van, start it, drive for 100 yards or so then no more pulling. Then he can put it in park, turn off the engine, restart it and drive for another 100 yards. The dealer said he needed a new transmission. I think it is something electrical. What do you guys think?