3.55 vs 3.92 rear end

[JustLuckey]

I know this is an old thread, but I wanted to add my 2 cents. I traded in my 2005 Ram 2500 Laramie w/Cummins for a 2016 Ram 1500 Laramie EcoDiesel. I opted for the 3.92 gearing (I think it was <$100 option) and I'm glad I did it. I don't haul and tow often (I tow a travel trailer 2-3 times a year), but on a recent trip to the Mtns of NC from GA, I hit many decent inclines (6-8% grades) pulling the 28' trailer (~6000lbs dry). I actually got a sick feeling on the way to pick up the trailer from the rental place thinking I might have made a bad decision to downgrade from the 2500 w/Cummins and that the 1500 Ecodiesel might be underpowered. But I was wrong. I'm so glad I opted for the shorter gears, as it pulled just fine. The taller gearing may not have been a wise choice, as at highway speeds with marginal incline (with Tow mode one/8th gear locked out), it was downshifting to 6th...and in rare cases 5th. I'm sure shorter gears would have down shifted further.
I'm all about fuel efficiency and from what I read, the difference is minimal between the 3:52. Since it had 8 gears, the only real difference will be seen in top gear. But to me, I like having a little bit of insurance knowing that I have the lower gearing when I need it.

 

[Reinmaster]

We ordered a Ram Limited Eco-diesel last December and took delivery in January, 2016. We didn't want anything on the lot and so we opted to specify our own wish list for options. Basically all the bells and whistles and the 3.92 rear end. We ordered the "Tow," package which as I found out limits you to 3.92 gears or so they told me. We live in Socal, and our city mileage runs 18-20 mpg. If I don't pay attention and drive normally, it's around 18-19. If I drive like a little old lady, I can get 20 mpg. On the highway, if I tank up before hitting the road, it varies between 26-30,depending on the incline. We have about 6,000 miles on the truck. At first I was a bit apprehensive about the 3.92's but now we just love this truck. Having driven a Hemi equipped version at the LA Auto Show about a year ago, this eco-diesel is almost as fast off the line. Don't know what they did to improve acceleration but it gets up and goes. We don't have anything to tow, this is actually the wife's car, so it's really just a "Mall-Crawler." I expect that as the engine breaks in a bit more the mileage may increase a bit more but we're happy campers with this engine, trans and rear end combination.

 

[HerbW]

In the end, I wound up buying an outdoorsman quad cab with the 3.92. It upped the towing and is pretty quick when accelerating. I live in a hilly area so I think it was the right decision and worth the sacrifice of a couple mpg.

I recently also bought a new 2015 ecodiesel Outdoorsman in Black Forest Green Metallic Pearl with 3.92s and posi rear. I love the truck. It seems to stay at 2,000 RPMs no matter what speed I go. My best mileage is 24.6 MPG and worst is 21.2 driving in town. The MPG calculator in the truck is spot on! Only 4400 miles so far. Herb