I just bought a trans and was told it was th400, now her is the good part. The trans turns out to be a 700r4. Here's what I have !. My truck is a 91 Chevy full size truck 3/4 with 8 lug and I'm converting it to 2 wheel drive so, I've went out and bought new drive shaft and all my parts thinking I had th400 and my slip yoke is to big , go figure . A th400 has a 32 spline and 700r4 has 23-27 I think. Question! can I use the 700r4 with a 9" tail shaft and use my transfecase to keep my truck a 4x4. don't think I can but if someone has any IDEAS I'm open to all.