69 lemans tranny

[ezsk8er66]

i have a 69 lemans, automatic transmission, its only got low and drive, and i picked up a 69 firebird transmission which is a three speed, the car it came from was an origional 400 car, i was wonder if it is possible to mount the firebirds trnny to my lemans
any help is appreciated,
thank you

[maxwedge]

PwrGlide to a TB 400? correct, if so the flywheel, convertor, driveshaft and trans crossmember are different, but all the parts can be sourced and installed if desired. Also 8 cyl we presume, this info left out. Per forum rules double posting is not allowed, I will delete the other post. Thanks.

[MagicRat]

A '69 Pontiac with a "Slip'n'Slide" (Powerglide) trans??

This is a long shot, but what engine does this LeMans have?

IMO it's unheard of to find a Poweglide behind a '69 Pontiac V8. However, a few found their way into Pontiacs with Chevy engines.

Soem Pontiacs got the Chevy straight six as a downgrade option. Also, there were lots of Canadian made Pontiacs (intended for the Canadian market) with Chevy six or V8 and a Powerglide.

So..... if you have a straight six (including the OHC version) or a Chevy V8, the Firebird trans will not bolt up to the engine. The bellhousing bolt pattern is different.

[MrPbody]

We hear this a lot. Pontiac didn't use PowerGlide on anything but the Chevy engines, as previously stated. The Buick/Olds/Pontiac 2-speed is known as Super Turbine 300, and shares nothing mechanical with PG. If your LeMans had a 350 in it, chances are, that was the trans (ST-300).

If the "new" trans IS a TH400 (pan shaped odd, kinda like Texas...), everything Maxwedge said is correct. All "400" cars would have TH400 if automatic. However, TH350 was in the Firebird with the 350 engine. If it has a pan that's rectangular, with one corner "lopped", it's a TH350, and will bolt right in, as all the important lengths are the same. Shifter can be fun...

Jim