ST400 TRANSMISSION KIT

[1964KX]

Trying to find a basic rebuild/refresh kit for my ’65 ST400 variable pitch transmission, most I have seen just are listed for ST400 and don’t specifically say it for the switch-pitch trans.  My question is are they the same kit for both ST400 whether it’s a switch=pitch or not and can anyone point me to a source or a brand name and kit number?

[rocketraider]

The transmission internals will be the same. 400 kit may not come with the torque converter angle switching solenoid.

 

FATSCO, Northwest Transmission, Edwards, any of those should be able to steer you right.

[drhach]

Yup. I rebuilt mine. The pump is the different animal. Seals, bands, etc. all interchange. You may also find that the output shaft bushing is smaller than most ST400/TH400's. Mine is from a 65 and they used a smaller diameter bushing and yoke. But if you're bushing are ok, you'll be fine with the generic rebuild kits. 

 

There's actually a plethora of upgrade stuff that you can do if you want to go there. But you sure don't have to. You my also have a unique oil filter. But again, nothing you can't source or swap if you aren't a purist. 

Edited May 6, 2022 by drhach (see edit history)

[1964KX]

Actually, my Riviera is a '64, I want to install the '65 switch pitch trans for a few reasons, I have a performance camshaft which was ground, or at least offered, by Posten Buick in Alabama, which I don't think is in business anymore.  It was advertised in their catalogue as being the camshaft Buick should have installed in the KX/LX engines back then instead of the normal 4 bbl cam the engines came with.  It is said to have "slight lope" and I've read the variable pitch trans could help with that at idle.  I also have a few numbers correct factory 2x4 set-ups that I plan to install one of them when I do the cam and trans swap; a shift kit would also be a good upgrade if I can find one for the rebuild.  So basically I'm working toward what was offered as the "grand sport" option in '64 but not called that till '65, the car already has the 3:42 posi rear,,,

[RivNut]

Search the old issues of the Riview for a Q&A answer about camshafts that was written by Dennis Manner, a Buick engineer who actually dealt with the nailhead cams in the day.  You'll be surprised at what you find regarding the 2x4 cam when compared to others from different nailheads.  And as Jason Zebrini answered your question, that Poston cam isn't that much different from a stock Buick cam. 

 

The Gran Sport option in 1965 consisted of the A8 engine, the BS transmission, the 3.42 positrac rearcend and "special badging."  In 1964, it was only the A8 engine. A posi rear end was available as a separate option, and the ST400 transmission did not have the variable pitch feature.  In 1964, you got the A8 engine in a regular Riviera with whatever other options you ordered separately.

[1964KX]

14 hours ago, RivNut said:

Search the old issues of the Riview for a Q&A answer about camshafts that was written by Dennis Manner, a Buick engineer who actually dealt with the nailhead cams in the day.  You'll be surprised at what you find regarding the 2x4 cam when compared to others from different nailheads.  And as Jason Zebrini answered your question, that Poston cam isn't that much different from a stock Buick cam. 

 

The Gran Sport option in 1965 consisted of the A8 engine, the BS transmission, the 3.42 positrac rearcend and "special badging."  In 1964, it was only the A8 engine. A posi rear end was available as a separate option, and the ST400 transmission did not have the variable pitch feature.  In 1964, you got the A8 engine in a regular Riviera with whatever other options you ordered separately.

Thanks for your comment; yes, having a '65 Gran Sport I am familiar with the options, the question keeps getting different comments about the camshafts, some say it's different, some say it's not, 4bbl 425 vs. 2x4bbl 425.  Over a long period of time I have always found the cams are the same for both versions of the 425 in '64/'65 and that the '59-'61 401 cams were the most radical.  As I said previously, I don't know much about camshafts and am saying only what I found on the internet which I know isn't always correct.  I posted a listing of cam specs for the nailheads on my other post concerning that subject, it seems to indicate those cams are the same; what is your take on it?,,,thanks again

[telriv]

It is the '59 cam retarded 4*.

 

Tom T.

[RivNut]

Find Dennis Manners’ article for the complete break down of ‘59 - ‘66; 4 bbl and 2 x 4bbl nailhead cams, casting numbers, part numbers, and specs.  Yes, the ‘59 401 cam is the most aggressive.