Np420 shifter housing question

70w100 · Post by **70w100** » Tue Jun 25, 2013 10:51 pm

I have two np420 transmissions one in a 70 w100, 318 and the other in a 68 d100, slant 6. They both have the same casting number C91781 but have different tops. The trans in my 68 has the shifter closer to the firewall. Are the housing tops interchangeable? The reason I ask the np420 in my 68 wont shift into 4th gear. It shifts fine in all other gears. I know it's time for a rebuild and I'm waiting for the bearing kit to show up. I just want to know if maybe someone slapped something together or if its supposed to be like that? Also the 68's bell housing is different with dual engine bolt patterns and a totally different starter.