2015 3500 Ram

Love my 4.10 rear end. Personally I would not get any less than a 3.72, but you have to understand ratios, torque, and load handling further to see my point. The 3.42 will work, but he might be towing in 5th when I tow easily in 6thOD.

YES it is quite adequate.....good towing

Motor/transmission with that gearing will tow that 16K all day long and get good mileage

Not the optimum combination, but it will work.

Rusty

The rear end may be a 3.42, but what matters is the overall gearing. Lower gears in the transmission will allow higher gears in the differential.

fj12ryder wrote:
The rear end may be a 3.42, but what matters is the overall gearing. Lower gears in the transmission will allow higher gears in the differential.

It almost certainly has the 68RFE automatic, not the optional Aisin AS69RC. In both transmissions, 5th and 6th gear are overdrives, and 6th has almost identical ratios of ~0.615:1. Aside from overall gearing that's too tall in 6th with the 3.42 axle, 1st and 2nd gear in the 68RFE are higher (lower numerically) than the Aisin which will make starting from a stop on steep slopes more challenging that it would be with a 3.73 or 4.10 axle ratio or with the Aisin transmission.

The easiest way to determine which transmission the truck has is to look under the hood. If the transmission dipstick is on the passenger side, it's a 68RFE. If it's on the driver's side, it's an Aisin.

Rusty

If at all possible, get the 4:10. Your friend will thank you. My in laws had the 3.42 in their 2010 and my 2012 had the 4:10's and I would walk away from him on the grades and I had 4K more pounds of fifth wheel. He has the 43 foot XLR toy hauler and I the 43 foot Mobile Suites. He has since purchased the 2014 with 4:10's and I the 16 with 4:10's again... Crazy cycle...

YnotTurbo wrote:
My in laws had the 3.42 in their 2010 and my 2012 had the 4:10's and I would walk away from him on the grades and I had 4K more pounds of fifth wheel.

The Cummins in the 2010 was rated 350/650 while the Cummins in the 2012 was rated 350/800. Torque matters, too. (And yes, I had 4.10s in my 350/650 2011 and in my current 385/900 2016.

Rusty

I have the same gears, I tow near 30K pounds of equipment and steel with no issues and Im not a dually. Dont give it another thought.

Im insured for the weight, so the number nuts can relax.

We have the CTD with the 3.42s and we are pulling our 15.5K Fifth wheel just fine.

Went to the great lake Ontario back in September from eastern Connecticut and it pulled the trailer amazing.
Doing 65 easily up hills and not having to get on the gas at all just held steady.
from a dead stop she easily got up to speed and for the most part held steady at 12.3MPG.
Had a full water tank and full fishing gear for 4 adult guys for a week.

I thought I wasn't going to be happy with the gears but it works great so far. No complaints here

Both transmission will work at the weight, however the Aisin will be much better at getting the load moving forward. In reverse the 68RFE wins with a lower reverse ratio. Chris