# Powerglide or jetway trans



## sixtysix (Jul 2, 2010)

I have an all stock numbers matching 66 GTO. It has a 2 speed automatic trans. The numbers that are stamped on the lower servo cover are 66 NA237N.
I thought it was a powerglide trans. but I am not 100% sure. I also read that the powerglide didnt fit the pontiac engine. The trans that was used is an st300.What was the jetway trans? was that just used in oldsmobile? Can someone help me find out just which trans it is? Thanks.

66


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## blackplate65 (May 10, 2011)

300 is what my trans guy called mine also


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## Instg8ter (Sep 28, 2010)

yes it 300 is not a true powerglide, almost a hybrid between the PG and the TH350.


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## freethinker (Nov 14, 2009)

sixtysix said:


> I thought it was a powerglide trans. but I am not 100% sure. I also read that the powerglide didnt fit the pontiac engine. .
> 
> 66


they never made a powerglide to fit the the bop bolt pattern.


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## ALKYGTO (Mar 29, 2010)

"Super Turbin 300" is also air cooled. Big holes in the bellhousing.


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## 05GTO (Oct 6, 2004)

The ST-300 was also known as the Jetaway used in the Oldsmobile and Buick A-bodies and it is the same transmission used in the Tempest line.

NA is a 66 Pontiac GTO Transmission Code and 237 is the Julian Date for a late August (24th) production date.

The powerglide and the ST300 have no interchangeable parts. Chevy did however use the ST-300 in some models with the inline 6.


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## geeteeohguy (Feb 2, 2008)

Your 2 speed '66 GTO came with a Superturbine 300. This is not a powerglide. It is a bulletproof, if not a performance improving, transmission. The air cooled ones came on 6 cylinder cars....the v8 applications were conventionally cooled, with a trans cooler in the radiator. Good solid trans, but with a 1.76 first gear and a 1.00 High gear, it will slow a car down out of the hole. A TH350 or TH400 swapped in will literally change the feel of the whole car. It will feel like you picked up 100+ HP.


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