So my 2.7 is blown and I am looking for a 3.5 to replace it. My question is will I need to get a 3.5 tranny as well or will my 2.7 tranny be able to take it? The tranny has less than 68.5k on it. Also are there any other drivetrain parts to replace (exhaust, manifolds, drive axles, etc)?
But to answer your question about the transmission - it is the exact same transmission except the final drive gear ratio is different - but sometimes the 2.7 gear ratio (3.89) is more desirable for performance than the 3.x ratio (3.66). If you want slightly better economy though, you would want to get the other gears, or whole transmission (but no other need to).
You will have to shorten the passenger side exhaust by 2" - I THINK - wait for an expert to chime in on that though.
And personally, I think it is easier to change the engine by pulling the engine and transmission at the same time, splitting them on the floor, then re-assembling and dropping in as a unit. A load leveler for the engine crane is a good thing. I use this one: (on sale now for $35)