So the shop tells me my transmission is toast, looking to buy a used one and swap it out. I believe all 2002 models used the 5R55N (but correct me if I'm wrong). However, when I look online for 5R55N granny's online, I see two variations, one is the 1W4P-AA and the other is 2W4P-AA. How do I know which one is correct for my car? I've read some articles saying they changed from one to the other part of the way through the year, how do I know for sure which one I need, don't want to be wrong and be stuck with a tranny that won't work. Is there a way to know without dropping it? My car has a manf date of 04/02 if that helps figure it out.