Super duty rear ratio!

For that weight a 3:55 would be fine.

I have a F250 with 3:55 and tow about 10000# no issue and I pull in the Rockies a lot

muddyriver wrote:
I'm starting to research buying a new truck. I'm defiantly going diesel this time and wondering what rear end a person should get. I'll be towing a camper around 9K. with about 1200K in the box of the truck. I'm hoping to buy used. My 6.2 had 3:73 which pulled our 8600# camper well, but wish it would have had the 4:10 in it. Does a person go to 3:55 or stay at 3:73 or even move up to 4:10. I would appreciate peoples information. Kind Regards, Nathan

We have the 3:73 and it does fine. With the power the newer diesels have, one could go with the 3:55. Being that you are buying used, you should research the specs (especially the torque) of the diesel engine. When we are towing and I am in "tow mode" usually the (transmission) will not shift into 5th gear until 60 MPH. I am used to it now, as we have owned this truck for 14 years. Hope this helps............Bruce

Unless you’re looking at a drw f350 the diesel in the f250 and f350 srw options are 3.31 and 3.55, the 3.55 are automatic if you go for 20” wheels. Any version of the diesel super duty will pull that TT.

I just got a 2017 (in my signature) and it's got the 3:31 rear end, and it's not locking, or even limited slip... It's the truck that I could find and afford mind you. I'm not going to campaign for my set up. I do not have experience towing with the other ratios... AND... I've only towed about 300 miles with this setup so far...

With those 4 million disclaimers stated... I can not believe how much better this truck tows than my 2010 5.4L did. My trailer is at least 8300# (Dry/Fantasy weight)

Back to the truck... This engine paired with the 6spd tranny... It's an amazing difference in experience. I guess in short (and other opinions may vary widely) I would not shy away from the 3.31 if the rest of the truck was want you wanted ( you said looking used)... If I had the budget to order whatever I wanted, well.... Haha..

Anyway - just one Man's (limited) experience with the 3.31 - take it for whatever. :) I loved my old "Blue Monster", but, I don't want it back! :-)

I have a 2012 F350 6.7 with the 3:55. Tows the 12,000 lb 5er fine over CO mountain passes. Cruises at 70 in 6th on flat to rolling highways.

Even with 3.31 rear axle gears that truck will tow the snot out of a 9K trailer, or one twice as heavy for that matter. The diesel has over twice the torque of the 6.2 gas. Comparing with a 3.73 equipped GM truck is not valid comparison since the Ford has lower transmission gearing. A 3.31 equipped Ford has more aggressive overall gearing than a 3.73 equipped GM.

As has been said 3.55 is your only option with 20" wheels. With 18" wheels either 3.31 or 3.55 is available. I have 3.55 gears with 20" wheels and the truck pulls my 16000 lb RV eaaily. I would recomend 3.31 if your happy with 18 inch wheels.

Is there a possibility that you will buy a bigger camper in the future?

Just to add to what’s been said; the 2015 F350 I had came with the camper pkg, which included 3:55 ratio on 18” wheels. But many are pulling bigger trailers than yours with 3:31’s just fine. If you find a truck that’s otherwise equipped as you want, I wouldn’t let it stop you. Good luck in your search.