I have a 2008 with a 5.5 and its 4x4 with 3.73 gears. I recently put on 305/55R20 Nitto Terra Grapplers and as you can imagine (and I knew it would happen and yes I know I have a truck) my mpg and performance declined. If I were to re-gear to 4.54 would that do anything for my engine performance and my mpg? Will it bring it somewhat back to stock?

 

ha first of its a 5.4 and the gear ratio you're refering to would be 4.56's. that size is around a 33in. tire. 4.56's would be a pretty low gear for them. you would have more bottom end but 4.10's may be better. most people don't bother regearing though until they get above 35's.

 

Have you tried a programmer ? You will be amazed at the difference they make in power.

 

X2

 

Big performance upgrade. Big decrease in highway MPG.

 

+ you'll save about $600 or so

 

Just curious, What an average gearing change, Parts , materials, and labor would be on a 4x4 ? I wouldnt mind going to 4:11's now that I'll be aproaching a 33" dia. with my new 305/45/22's.

 

I could be wrong, But I think I remember seeing 1k-$1500... possibly even more. Its the install that will kill you.