I'm swapping a 4l60e out of a 01 formula, and havnt decided if I'm going th400 or 700r4. Which one is better and what all will I need to swap it. Im sure ill need a new stall converter but what about the pcm or wiring harness? Any help would be greatly appreciated.

 

We just had a very similar thread:

https://ls1tech.com/forums/automatic...nsmission.html

The 700r4 is a weaker version of the 4l60e and would be a bad choice.
A TH400 would be stronger, but not have OD for street driving.
A TH400 does not require a PCM or wiring harness; however your PCM would need to be tuned to remove the trans codes.

 

A 700R4 Isnt necessarily a bad choice. It was earlier than the 4L60E so it was prior to a lot of the updates that the 4L60E saw but it still is not a bad transmission when built correctly even without a lot of the updated items that came much later. Pretty much all of the updates that the 4L60E saw can retrofit back to the 700R4 as well and without a lot of trouble.

That being said I am not sure why you would want to replace a 4L60E with a 700R4 or a TH400. I can not see much benifit to doing either. If anything maybe a 4L80E but I am not sure that is really necessary either..

 

I would try to get the 80 if you enjoy cruising.. A 400 can be a strong Trans when built, but I can't stand not having overdrive. To try and see if you would like it, hold your shifter in D while going down highway about 60 or 70..