Which rear end?

[mor4wd]

Who on here has the 3.55 rear and vs the 3.31? How do you guys like it? What kind of mileage differences are you guys seeing. Post up your rear end and your mileage please. I'd like to see which ones are better. They are both rated to tow the same I believe. Thanks guys.

[surveyor13]

I've got a 350 and I have the 3.55 e-locker. Had to get it to get the 20" wheel option. Just went from Atlanta, GA to Bend Or and from Bend, OR to Pittsburgh PA. I got anywhere from a low of 12 MPG to a high of 17.6 MPG on this trip and I was mostly running 80 MPH. The worst was going through Wyoming, Utah, Idaho and Oregon. I guess due to air temperature and winter blend fuel. I was not towing anything. Only real difference was on the way back I had 300 pounds in sand bags on the rear axles in the bed of the truck for traction. My *** end was all over the place in Wyoming on the way to OR with the winter storm that had moved through. Not that 300 pounds is that much but it helped a lot on the snow and ice I went through on my way to Pittsburgh PA. Current odometer reading sits at just over 19,000 miles.

[PUMPED 101]

^ that is a lottttttttttttt of driving

[djc1208]

Originally Posted by mor4wd

Who on here has the 3.55 rear and vs the 3.31? How do you guys like it? What kind of mileage differences are you guys seeing. Post up your rear end and your mileage please. I'd like to see which ones are better. They are both rated to tow the same I believe. Thanks guys.

=====================================

I own a F250 CC SB with a 3.31 rear end 4550 miles on her and get 18-19 Lite Town driving, 20-22 at 65-70 and 24 MPG on the highway at 55.. I just got back from Houston for the Holidays and got 20 going over with head winds and 22 coming home all at 70 MPH... Love my Diesel just wish I had gotten the long bed and the 37 gallon fuel tank..... Hope this helps!
Don

[surveyor13]

Originally Posted by PUMPED 101

^ that is a lottttttttttttt of driving

Yep. I leave the Pittsburgh area on Thursday headed to Houston Texas, in Houston till the following Thursday headed to Atlanta, GA to pick up my daughter and the over to Grenada MS for a family reunion. I haven't been in one place longer than 7 days since the middle of October.

[BlueF350]

I'm curious if you order the 3.31 with 18's and then swap out the 18's for 20's if you would get any significant improvment in mpg. Unless you're towing at the limit, I don't see how the 3.31 with the 20's would really impair the towing capability but could help with the mpg's. Thoughts?

[mor4wd]

The stock tire size on the 18s is about 33" tall and the 20's is about 34" tall. I'd imagine you'd see some gains.

[Anth]

Can you get the e-locker with the 3.31 rear end?

[mor4wd]

Yes you can get the locker with the 3.31. I went with the 3.55 locker after hearing you guys and talking to the dealer about it. I do some towing and the 3.55 seemed right.

[jflow730]

Yep. I leave the Pittsburgh area on Thursday headed to Houston Texas, in Houston till the following Thursday headed to Atlanta, GA to pick up my daughter and the over to Grenada MS for a family reunion. I haven't been in one place longer than 7 days since the middle of October.

I thought I did a lot of driving but it's nothing compared to this. Good thing about our area around Houston is that it is flat so you should see some good fuel mileage. Give a good loud honk when you pass through Beaumont for me.

BTW, if you have problems near Grenada, MS the Ford dealer there has a really good service department. I was going to Illinois on a hunt when my 6.0 took a dump. We left it in their hands and continued on our trip and the service guy communicated to me by text so not to interrupt my hunts. They had me over a barrel but they did a great job without unnecessary cost.