Rear End Gears: 3:21s or 3:92s?

Hey guys....new here. I've been looking at purchasing a Rebel to use as my personal work truck. I currently don't own a truck but I love the look of the Rebels. My brother in law has a white 2016 and it's pretty darn nice. I've more or less chosen exactly what I want for options and colour. My only thing I'm stuck on is the rear end gears with either the 3:21s or 3:92s. My new job requires me to do a lot of driving, both in the city and the highway. In the summer months, I'll be doing a lot of long highway trips towing a travel trailer. I also would be towing my muscle cars with it as well. The long highway trips leads me towards the 3:21s for better MPG since the engine will be revving lower. My brother-in-law has 3:92s in his and when we recently took it on a 12 hr trip to pick up a '71 Charger I bought, it seemed like the engine was revving a bit higher and the MPG wasn't all that great (140kph/87mph @ around 2,700 rpm lead to 19L per 100/12mpg). This is where I think the 3:21s would of come in handy. To those guys with 3:21s, on the highway, what does your truck usually sit at for rpms? Does the gears really make that much of a difference or am I wasting my time comparing them? My wife bought a brand new Wrangler with 3:73s instead of the 3:21s available and it seems to rev pretty high on the highway.




Now, while I am leaning towards ordering a new one, I did find a lease return local to me. It's about $7,000 CAD less then I can get a new one for and has about 6,500 km (4000 miles). It's exactly what I want colour and option wise but it has 3:92s. How easy is it to change the gears out for 3:21s? Is it just a simple gear set change?






Thoughts? Thanks!!