Quote Originally Posted by 00Daytona View Post
THANK YOU. I know it's not a plug and play swap. But yes the fact that the last generation Impala used both trans makes me think it would at least fit. As far as 4 speeds go I think the 4t65 is pretty great. Mine has 175,xxx miles on it and still shifts quicker than many of said newer trans. But it's days are numbered. It's gonna die, and if it does, I know it's worth it to try and make the 6 speed work.
Welcome and if you think a 175k mile 4tgarbage65 shifts good you've never drove or been in a car with a built 4tgarbage65. LOL!!!!

Honestly If your hell bent on keeping the car and using the 6 speed id just use the 3.6 along with it that way the computer is on the same page from the start. The 3.6 makes 300 hp anyways just as much as the LS4 v8 in the GXP grand prix. That would be way less hassle on the tuning side and everything would bolt right to the cradle.

This is what Ive talked about with Will @ Overkilled about in the past.

Buy the whole engine trans cradle drop out of a wrecked impala.

Then come the money issue. And its always is a factor I don't care what anyone says. Even an engine and trans combo from a wreck is likely going to be 2k plus easy since the 3.6 and that trans are used in many platforms its going to command pretty good chunk of coin.

That all being said the main reason most people that have done the 4T80 is because its got a way bigger chain in it and able to hold more HP.

If your just trying to get the 2 extra gears again Id be swapping the engine trans and cradle all at once to avoid the tuning problems.