65GS.com - Buick Gran Sport Enthusiasts!
Drivetrain => Transmissions => Topic started by: Rickesota on April 10, 2017, 10:27:01 AM
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As I said in an earlier post, I am installing a '68 Buick 350 in my '65 and currently keeping my ST300. The current 225 1bbl has the transmission control module. Does this transmission not have the ability to work with simple kick down linkage, or do I have to move this piece over to the new motor and get it to work with my new carb? Hoping to have a 4-speed manual next year so it'll be a moot point by then.
Thanks!
Rick
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Hello Rick
I you want the switch pitch to operate as intended you would need to use the electrics. Not all 300's used the switch pitch I think Pontiac did not use this option. My experience is the switch pitch in pretty cool if adjusted properly.
The ST300 (super turbine 300) transmission uses a two wire control and a vacuum line to control shifting. there is a small switch on the throttle linkage and a throttle position switch that handles the electrical signals to the trans. It is my understanding when the car is idle (stopped) the throttle micro-switch activates the switch pitch solenoid to allow less pull when stopped and the throttle switch engages the solenoid when the crab is opened up and when more throttle position is given (passing) the kick-down to first can occur.
Thanks Randy
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But will it still shift w/o the electrics?
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I am not an expert on this, but I have two cars with the switch pitch 300 and one of my cars had a 300 non-switch pitch when I purchased it. With-out the wire going to the kick-down solenoid (inside the trans) no signal will be given to the transmission and it won't downshift when you floor it to pass (passing gear). With-out the wire going to the switch pitch solenoid (inside the trans) no signal will be given to change the torque converter ratio, so at a stop sign more braking is needed (probably not a show stopper), and no increase in torque with an increase in throttle position; 1/2 to 3/4 throttle. The car will shift from 1st to 2nd (vacuum line must be connected).
I should say that if the 350 engine is used, I would go with the 350 transmission(pairing the original set-up). It has been my experience that the 300 switch pitch is a nice set-up if you understand how it operates. The 350 engine with the 350 three speed transmission should put a smile on your face as well. Messing with the 300 throttle linkage on a 350 engine could be a pain in the butt.
Obviously the engine compartment is going to be non-stock, at that point it is ultimately what do you want to drive and when do you want to hit the road!!!!
Sorry if I made things too complicated, but the Switch pitch can be a little confusing (especially for me).
Good luck, Randy
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Dear Rick, Randy, and mid-60s Buick owners with . . . never enough toys! . . . :icon_biggrin:
I should say that if the 350 engine is used, I would go with the 350 transmission.
(http://www.canebas.org/WeatherCat/Forum_support_documents/Custom_emoticons/wink.gif) . . . . A TH350!?!?! :icon_scratch: As long as you are going to suggest how about a TH200-4R! :angel4:
Not trying to tempt you Rick or anything . . . . . . (http://www.canebas.org/WeatherCat/Forum_support_documents/Custom_emoticons/conscience_smiley.gif)
Cheers, Edouard :occasion14:
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Since I am budgeting for a 4-speed conversion next year, the idea is to get it driving for the summer with my current trans and not have to buy another one. Worst case I can get the non SP ST300 from the engine donor car, if he hasn't junked it already.
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Hi,
You shouldn't need a different trans, if you don't hook up the switch at the carb, the switch pitch just won't work, and you will need to manually put it in first gear to pass, but should be fine for a short while as the v6 trans have fewer clutches and not as robost as one from a v8.
Good luck,
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So will it shift on its own during regular driving or will that be manual, also?
Thanks everybody!
Rick
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Yes it will upshift normally when you put it in drive, of you want it to drop in first to pass you will need to manually put it in 1st and then back in drive. It should start off from a stop and upshift correctly as well being left in drive.
The switch pitch feature gives you a different stall speed, but should not have any ill effects from not being used.
I drove a 64 that I swapped a 340 in and didn't reconnect the switch as I didn't have the right parts, and it shifted fine.
Just don't beat on it as like I mentioned previously, a V6/225 trans has less clutches compared to one from a V8/300 trans
Regards,
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Excellent! I can work with this until I get the manual next year!
Stay tuned...
Rick