I picked up a remanned GM 4t65hd that was in a 97 Regal GS but later found out that I need an internal range type trans for my swap. I picked up an 03 monte trans and was just going to take the diff from the hd unit and use it in the monte trans, but when I pulled the diff and the bottom trans pan off I found that this trans looks brand new on the inside....i mean it looks like it had just been rebuilt before the engine blew. My question is can i open up the side cover and just swap over all the electronics and wiring harnesses from the internal range transmission over to the external one and work, or would I be better off swapping all of the internal over basically as if I were rebuilding it? I've never dug into one of these other than swapping diffs and filters so I'm a little nervous about swapping all the main components as if I were doing a rebuild. I really hate the thought of totally ditching this fresh trans.Any advice would be appreciated. I'm doing a L32 swap in a Oldsmobile Silhouette with a northstar tb using a 2003 impala wiring harness and pcm if that helps.