[Tanner babb]

New to the forum and am looking to lower the gear on my 2013 Charger rt 5.7. Was looking at used ones and can find a ton of used 2006-2010 3.90 rear ends but will those fit our cars? Any input is appreciated

 

[djalbin]

I don't know if they will fit but if you do a lot of highway driving you may not want 3.90 rear gears. Depending on your tire size you will be at about 3K RPM when cruising the highway in 5th gear (I assume you have the NAG1 5-spd transmission). Below is a link where you can calculate your RPM & speed based on different gear ratios.

https://www.blocklayer.com/rpm-geareng.aspx
.

 

[Tanner babb]

Djalbin thanks for the info!