Early buick th400 question for the trans guys.

[1984dually]

Have a one year only 64 Buick th400. Has only a 5 position selector(p,r,n,d,l) instead of the usual 6 position(p,r,n,d,2,1) selector. Still a 3 spd trans. Question is the internals any different than the normal 400? Can I swap a later valve body onto it? Trans is clean inside but still will be freshend up before use. Done a few 400’s but this is a first for me. One odd thing is it has the normal BOP bell housing and I don’t think the engines in 64 had that pattern. 364-425 engines. Thanks for any info

 

[MarineOne]

If it is a 64 ST400, you have to use a non-switch pitch convertor. I knew the 64 Buick 400 were non-switch pitch, but I didn't know they had a PRNDL selector pattern. I just pulled out my old Motor's Automatic Transmission Manual and the 64 does have the PRNDL shift selector pattern. The oil schematic also shows that it applies the intermediate band in second gear. On the later 400's the band is only applied if you put in 2 (PRND21 selector pattern). It also states that you can get the car into manual second by moving the selector to L when you are above the low downshift point.

64 nail head st400 was a one year deal and if it has the bop bellhousing you've got a strange Mashup of parts for sure.

Sounds to me like someone swapped a newer engine and trans into a 64 nail head car and to retain factory shifter used the 64 valve body in it.

 

[MarineOne]

CENTERVILLEAUTOREPAIR.COM

More info available here

 

[1984dually]

Is strange that it has a bop housing. Could be that someone swapped cases. Is definitely not a switch trans. Maybe someone swapped housing But the tag looks undisturged. I got a couple other valve bodies that I will use and another bop case