3.5 transmission in a 2.7 300

[2.7hector]

so i got a 2.7 300 from a aunt and it had bad transmission so i got a 3.5 transmission for it will it work

[FIREM]

Need a little more information such as Year of car and donor car. Short answer is should bolt up. Due to power differences between engines final drive ratio is different.
A little more info and we a can guide you better.

[2.7hector]

so the donor car is a 2007 2.7 300 and the car we got the transmission is maybe a 2010 3.5 . i was having trouble with the 2.7 because after 40 mph it would just start over revving as it sped up. so me and my dad thought it was the transmission so we got a transmission from the junk yard

[FIREM]

Well my friend sorry to say I do not know the answer to your question with certainty.
We are very familiar with the LH series of Chrysler products from 93-04.
Your 300 is the later version LX series and may have some differences. I suspect the final drive ratio will be different and would recommend checking with a trans shop or a LX based Forum to be sure

[LUNAT1C]

You'll want to check something like LXForums.com, they'll have more knowledge about the 2005-2023 cars. This forums deals in the 1993-2004 cars, which are very different animals even though both platforms have 2.7 and 3.5 engines from 1998-2010. We have the 42LE 4-speed for FWD applications, you have the 42RFE for RWD/AWD applications.

It will likely bolt up, but I suspect controllers and wiring and final drive ratios will be different due to the different engine sizes, and the platform refresh in 2008 that made a number of electronics changes (I recall my 2007 Charger R/T would have needed some extra work if I wanted to use 08-10 electronic components).