65GS.com - Buick Gran Sport Enthusiasts!

Drivetrain => Transmissions => Topic started by: jmos4 on July 25, 2016, 05:15:45 AM

Title: ST300 transmission Shift Kit? (66 Article)
Post by: jmos4 on July 25, 2016, 05:15:45 AM
Hi all,

I've been doing so research on this 66 Buick article on modifying the valve body plate and wanted to know if anyone here has done this modification, as the article I have has a very hard to decipher picture on what hole needs to be opened from .090 to .125.

Regards,
Title: Re: ST300 transmission Shift Kit? (66 Article)
Post by: jmos4 on July 28, 2016, 08:06:11 PM
Hi all again,

Well after some searching on the internet I did find this on Russ Martins web site.

Also found out that there are 2 different valve body gaskets as mine did not have the A & B holes. So I did drill out hole C to 1/8" so will see if it helps.  Also found out that Trans-n-go was formerly Research from the article.  http://www.transgo.com/contact.html (http://www.transgo.com/contact.html)

As I had to call them to verify which gasket to use.

Regards,

Title: Re: ST300 transmission Shift Kit? (66 Article)
Post by: GreatScat1965 on July 28, 2016, 11:00:23 PM
Good stuff, I'll throw my 2 cents worth. When I bought my GS in 1994 it had a freshly built ST300 by someone in the Upstate NY area. Supposedly similar modifications were done to it. I can't verify that but the ST300 ST400 Guru at the time was Mark DeConti. He made a band adjustment based on old information like this and when he was done that was the best 2 speed I've ever driven. I like the ST300 and personally the biggest issue is no one seems to be able to get Idle micro switch set properly. A "gadget" switch as Pops Kennedy referred to it as is a must have as well. Rob (Stage 1 Performance) and I developed a 3 way switch for the switchpitch trans cars and it worked great. (Fully controlled by the micro switch and kickdown switch, high stall constant , low stall constant) all in 1 dash switch.

Full disclosure, I now have a fixed stall ST400 in the car but I really did like the ST300 with the 3 way switch.


Jerry
Title: What is an ST400 transmission? (Was: ST300 transmission Shift Kit?)
Post by: elagache on July 29, 2016, 11:08:20 AM
Dear Jerry and mid-60s Buick encyclopedias,

Full disclosure, I now have a fixed stall ST400 in the car but I really did like the ST300 with the 3 way switch.

Okay, I'll admit my ignorance.  I've never heard of an ST400 transmission.  Could somebody clue me in on what is this beast?

A curious mind wants to know!

Edouard  :occasion14:
Title: Re: ST300 transmission Shift Kit? (66 Article)
Post by: EZ Cool on July 29, 2016, 12:11:32 PM
ST400 (Super Turbine 400) is the predecessor to the TH400. although it had 3 forward gears it was not possible to manually control the 1-2 gear change. I believe it was only produced for the 64 year model. The SP400 came out the next year and it had a switch pitch converter and the 1-2 shift was manually controllable. I often wondered why the SP400 wasn't available in the GS behind the 401 nailhead. I am building a 65 GS clone and it is going to have a SP400.
Title: Such an evolutionary trail! (Was: ST300 transmission Shift Kit?)
Post by: elagache on July 29, 2016, 09:49:44 PM
Dear EZ Cool and mid-60s Buick evolutionary biologists, . . . .

ST400 (Super Turbine 400) is the predecessor to the TH400. although it had 3 forward gears it was not possible to manually control the 1-2 gear change. I believe it was only produced for the 64 year model. The SP400 came out the next year and it had a switch pitch converter and the 1-2 shift was manually controllable. I often wondered why the SP400 wasn't available in the GS behind the 401 nailhead. I am building a 65 GS clone and it is going to have a SP400.

WOW!  I had no idea of this evolution of GM transmissions.  This actually makes much more sense with all these missing details.

THANKS!  :icon_thumright:  That's what makes this forum da' real McCoy! . . .  :glasses9:

Cheers, Edouard  :occasion14:
Title: Re: ST300 transmission Shift Kit? (66 Article)
Post by: gs spoken here on July 30, 2016, 09:32:08 AM
Does Transgo make a shift kit for a ST300?
Title: Re: ST300 transmission Shift Kit? (66 Article)
Post by: jmos4 on July 30, 2016, 11:05:36 AM
Hi,

Transgo doesn't make a "shift kit" this article is what I found searching online for tweeks to improve the performance of a st300.  I am sure if you gave the article to someone rebuilding a transmission that they could incorporate it.

Also I got my gaskets from Fatsco, and up until yesterday they were unaware thete was 2 different valve body gaskets, even though they had sent me both types, so I believe if you go for this modification get both types so your not left waiting for the correct one.

I have yet to get my car going to see what difference the hole size makes, will let you all know.

Regards,
Title: Re: ST300 transmission Shift Kit? (66 Article)
Post by: GS66 on July 30, 2016, 11:45:54 AM
Good luck! It will be interesting to hear your report.
Title: Re: ST300 transmission Shift Kit? (66 Article)
Post by: jmos4 on June 24, 2018, 07:29:39 PM
Hi all,

Finally got some miles on my project, mostly driveability issues.

Well the article modifications do help, much firmer shift, still no rocket ship, but much better than any ST300 I can remember.

Regards,