How to Rebuild a Super-Turbine 300 (ST-300) - A Pictoral Essay

Discussion in 'The "Juice Box"' started by Kirk, Jan 16, 2006.

  1. Kirk

    Kirk Well-Known Member

    Followed by the Vacuum Modulator. These two 'sense' the load on the engine via the vacuum, and modify the shift point accordingly.

    Attached Files:

  2. Kirk

    Kirk Well-Known Member

    Now, slide the Governor in place, its gear engaging the splines on the tailshaft.

    Attached Files:

    Last edited: Jun 22, 2018
  3. Kirk

    Kirk Well-Known Member

    Finally, install the Governor cover and gasket and tighten its bolts.

    Attached Files:

    Last edited: Jun 22, 2018
  4. Kirk

    Kirk Well-Known Member

    You're done! Just add a dipstick, a few quarts of ATF, stick it in the car and have fun!

    Attached Files:

  5. Freakin Awesome!!!
  6. Babeola

    Babeola Well-Known Member

    Thanks Kirk,

    That must have been a lot of work to upload! This and the Chassis Service Manual should cover it for most! I wonder if the Mods could put this in one long post and lock it?

    Cheryl :)
  7. I like the long post idea, and I would recommend it for a "sticky", but I would not like it locked. While locking it would do away with general banter posts, like my compliment, it also does away with a direct place for people to ask questions about the subject matter. That leads to more topics about it, and general fragmentation.

    :Do No:
  8. Kirk

    Kirk Well-Known Member

    It took about an hour to actually post the pictures. Before that I spent a lot of time resizing the pics to 640x480, enhancing the colors on some, writing the text, checking for mistakes, etc.

    It's the same format I followed on my "How to Rebuild a Rochester 2GV Carburetor" thread. It's a surprising amount of work, especially taking the photos in the first place (stop what you're doing, arrange the parts, snap a pic or two, start working again). And there's a lot I simply forgot to photograph in the heat of battle. That's why I mentioned the "Chassis Service Manual". The factory manual is quite detailed and very easy to follow. This pictoral essay is simply proof that mere mortals with home-made tools can actually rebuild a transmission, too.

    A lot of effort to post this, but worth it. This forum has helped me out with my Skylark, so I like to return the favor in some small way. Perhaps these posts will help out another member.

    Thanks for the kind comments!
  9. buicksstage1

    buicksstage1 Well-Known Member

    :beers2: Great post, make it a sticky! I did a timing cover post and it to was painfull because I had to keep stopping to take pics. Chris
  10. telriv

    telriv Well-Known Member

    SOOOOOOO, how has it been working for the last couple years. What kind of vehicle????
  11. Dmagnolia

    Dmagnolia New Member

    Nice job on the pictures. There are two videos of a Super Turbine 300 being rebuilt at on the video page. It's not instructional video, but you can see what it takes.

    Let me know if it helps.
  12. D-Con

    D-Con Kills Rats and Mice

    somewhere wayyy back when I posted a scan of a magazine blurb showing where to drill the valve body spacer for quicker shifts. I also wonder if a TH400 shift kit might make a good donor for a stiffer regulator spring.
  13. ancientx

    ancientx horn/antler&bone carver

    Cool thread as I've been thinking of doing this too. A couple of questions for the guys more "in the know" than me.

    First: Where do I find the rebuild kit? Does it include the pumps?
    What about new solenoids?

    Second: I read on another(multiple) thread about relocating a solenoid into the pan. Where/how should this be done?

    Third: Any tricks to improve the capabilities of an ST300?

    Lastly: Since it's an oil strainer and not an actual filter, could a filter be used inline to the cooler @ the radiator? If so, what would you use? Would it need a pump?

    Any info on this would be great. This would be my first tranny rebuild and I'm a bit intimidated. Thanks
  14. ancientx

    ancientx horn/antler&bone carver

    *bump*nudge*:Do No: I really have no idea where to look for this stuff. Or what I need to buy.
    I'd love to have JB build up one of the Olds ST400's I've got, but I don't have the $$ for that right now. I'll be getting a replacement from a donor 'Lark tomorrow. I'm hoping it'll last until I get the original rebuilt. And I really want to do it my self.
  15. Kirk

    Kirk Well-Known Member

    Actually, quite well. Except I didn't take the time to straighten out the mounting flange on the oil pan so it still drips ATF. Oh well - the next time I change the tranny fluid I'll fix the pan once and for all, though I keep saying that every time....

    The tranny is mounted in a '68 Buick Skylark convertible. Rebuild parts are still available but you have to be specific - mention two-speed tranny for a GM car and *everyone* responds, "Oh, a Powerglide!"

    It's not - other than the fact it has two-speeds and was sold by GM the Super-Turbine 300 is a completely different animal from the Chevrolet Powerglide.

    I bought my parts from

    While rebuild parts ("soft parts", like clutches or gaskets) are readily available, hard parts are not. It took me quite a while to find a usable oil-pump - GM only made the ST-300 in the 1960's and nobody keeps them around. *Everyone* told me to get rid of it and just drop in a Turbo-Hydramatic.

    Well, although pretty close, a TH-350 is not a drop-in replacement (though not a difficult conversion, either). And this is a numbers matching car (yup, there is a VIN-matching serial number on the tranny). Plus I just like the idea of a nostalgic 2-speed, "Low and Go", PRNDL and nothing else, floor it on the highway and it downshifts to FIRST, etc., etc.

    So I persevered and found a good oil pump (I *think* I found it at My original was trashed when I ignored a cracked flex-plate for too long. Sure, it made a funny click at idle, but it still ran and I didn't want to drop the tranny just to replace a flex-plate. Except the cracked plate allowed the torque converter to slide fore and aft a bit. As the crack progressed the torque converter slid forward and unhooked from the oil-pump drive gear, then slid back without the slots engaging the tangs on the gear. This meant the gear was now pressed hard into the pump housing, grinding metal on metal. And I continued blissfully driving....

    When the tranny started shifting funny I checked the dipstick and the oil looked like gray toothpaste. :(

    Hence the rebuild.
  16. roverman

    roverman Well-Known Member

    >Thanks for all the pics/info. Is this trans useable for drag racing ? What PG race parts interchange w/o using switch pitch ? Manual valve body with trans brake ? Engine is approx 500 hp. stage II V6. Thanks, roverman.:TU:
  17. telriv

    telriv Well-Known Member

    like mentioned in post #191, "It's a completely different animal than a PG!!!!
  18. RA462

    RA462 New Member

    Hey Im new here and ran found this post searching for informationon the Super Turbine 300. I have a ST-300 and a 1.76 Powerglide apart in myshop right now side by side. Im no trans. expert by any means but have rebuilt10 or so transmissions before (never a ST-300).

    What I have found so far is this. The band and clutches arethe same between the two transmissions. Also the planetary gears on the ST-300are 20% wider. Gear ration is 1.76 for both. The modulator is the same as aTH400. From what I have found out looking into the Powerglide is that the planetarygear set should be replaced with aftermarket straight cut gears at around 750HP. So if stock glide gears are good for 750 HP I would think the ST-300 wouldbe good for 900 HP?

    Why am I doing this? I would like to replace the TH400 in mydrag car with a Super Turbine 300. Ultrabell for the Powerglide is like $275and $750 for straight cut 1.80 planetary. ST-300 will bolt right up to myengine and I have between 750 and 900 HP. I want to give it a shot!

    Now the hard part is Im looking into is can I make atransbrake for this thing.

    Good reading and nice pictures in this thread. Thanks
  19. CLP

    CLP New Member

    Kirk hello I am looking at your transmission post getting ready to rebuild my ST 300 two speed transmission now I have the 65 Pontiac Lemans which has the exact same transmission and I also have the service manual showing step-by-step on how to do it I do have a couple questions I like how you made the spring compressor out of the two by fours, was wondering if that was the only specialty tool other than snap ring pliers that you needed . And also in the service manual gay Mike out a couple of the clearances was that necessary did you have to do that ? And was wondering the best reasonable vendor to get the master rebuild kit from don’t want to spend a whole lot of money thanks for your time for your post and your knowledge
  20. Mark300v8

    Mark300v8 New Member

    When putting the seal around the foward clutch piston does the lip face up or down?

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