th400 - np 203

[towdriver80]

Hi, I was reading some of the old stuff on here, and think I`ve hit a snag in my th400 swap. Truck came with a th350/np 203. I`m putting in a th400 from a fullsize one ton pickup, that was mated to a np203 also. Is the np203 from my truck going to fit? I have the adapter that came with the th400. Thanks again.

 

[Hossbaby50]

No, a 203 that was behind a TH350 had a 27 spline input gear. The 203 from behind the TH400 had a 32 spline input gear.

The TH400 version 203's are usually pretty expensive if you buy them by themselves because that is the 203 you need to do a TH400 doubler setup. That drives the price of that 203 up a pretty good amount along with the fact that they are not as common as TH350 version 203's.

Harley