Reply
 
Thread Tools Search this Thread Display Modes
 
Old 07-17-2015, 12:39 PM   #1
4 Rivet Member
 
carver 1's Avatar
 
2011 30' Classic
2007 25' International CCD
1993 32' Excella
Largo , Florida
Join Date: Nov 2013
Posts: 355
Images: 30
3.31 or 3.73 Differential

On the 6.7 F-250, which is the preferred rear end differential ratio?

Thanks,

>>ron<<
__________________

__________________
2015 GMC Denali 2500, 4x4, Duramax diesel, Topper, Pro Pride 3 P, Sendel 16" with Michelin LTs, one Yellow Labrador Retriever (AS security)
carver 1 is offline   Reply With Quote
Old 07-17-2015, 01:13 PM   #2
Moderator
 
DKB_SATX's Avatar

 
2017 26' Flying Cloud
1976 Argosy 28
Alamo Heights , Texas
Join Date: Aug 2006
Posts: 6,401
Images: 1
Blog Entries: 7
For '16, I don't think the 3.73 is even available on a 250 with the diesel, you have to get into a 350 DRW. All their specs list is 3.31 and 3.55 for the F250 with the 6.7L. Even for a 30' Classic I'd think that 3.31 would do OK with 860 lb-ft of torque at 1600 RPM, and the 3.55 would probably drag it pretty well even without wheels on the trailer.
__________________

__________________
David

Zero Gravitas 2017 Flying Cloud 26U | Il Progetto 1976 Argosy 28 Center Bath | WBCCI# 15566

He has all of the virtues I dislike and none of the vices I admire. Sir Winston Churchill
DKB_SATX is offline   Reply With Quote
Old 07-17-2015, 02:21 PM   #3
3 Rivet Member
 
2010 28' Flying Cloud
Slidell , Louisiana
Join Date: Nov 2009
Posts: 101
Have 6.7 with 3.31 towing 2010 28ft FC usually with about 800 lbs of tools & 8.5 genset in bed. Effortless tow even across Rockies but minor concern is 1st gear wheel spin on quick starts from traffic lights, especially if damp or Sandy pavement, or when turning while starting from stop and occasional tire chirp on 1-2 shift. Don't need any lower gearing.
__________________
dayner is offline   Reply With Quote
Old 07-17-2015, 02:35 PM   #4
Moderator
 
DKB_SATX's Avatar

 
2017 26' Flying Cloud
1976 Argosy 28
Alamo Heights , Texas
Join Date: Aug 2006
Posts: 6,401
Images: 1
Blog Entries: 7
I just happened upon an article about Ford's commercial vehicles... the F650 and F750 also use the 6.7L as one of their powerplant options... and in the hottest of the 3 tunes it's putting out 330hp and 725 lb-ft. of torque. This in a truck that's going to do WAY more work than probably 95% of F250s on a day-to-day basis. It speaks to what ludicrous overkill the numbers battle between the big 3 has become... the F250 is tuned for 440 hp and 860 lb-ft of torque. I wonder how much longer they'd last tuned like an F750.
__________________
David

Zero Gravitas 2017 Flying Cloud 26U | Il Progetto 1976 Argosy 28 Center Bath | WBCCI# 15566

He has all of the virtues I dislike and none of the vices I admire. Sir Winston Churchill
DKB_SATX is offline   Reply With Quote
Old 07-17-2015, 02:45 PM   #5
TinCan
 
graysailor's Avatar

 
2016 30' Classic
Apache Junction , Arizona
Join Date: Aug 2011
Posts: 798
I have read on several Ford forums that the 3.31 rear end for the F250 diesel works just fine. The only difference is perhaps just a tad better mpg. I have ordered my Lariat with the 3.31's
__________________
TinCan
graysailor is offline   Reply With Quote
Old 07-17-2015, 02:48 PM   #6
4 Rivet Member
 
carver 1's Avatar
 
2011 30' Classic
2007 25' International CCD
1993 32' Excella
Largo , Florida
Join Date: Nov 2013
Posts: 355
Images: 30
Quote:
Originally Posted by DKB_SATX View Post
For '16, I don't think the 3.73 is even available on a 250 with the diesel, you have to get into a 350 DRW. All their specs list is 3.31 and 3.55 for the F250 with the 6.7L. Even for a 30' Classic I'd think that 3.31 would do OK with 860 lb-ft of torque at 1600 RPM, and the 3.55 would probably drag it pretty well even without wheels on the trailer.
The reason i am asking is that I am looking at a 2012, F-250 XL that comes with the 3.73. Appreciate your response.

>>ron<<
__________________
2015 GMC Denali 2500, 4x4, Duramax diesel, Topper, Pro Pride 3 P, Sendel 16" with Michelin LTs, one Yellow Labrador Retriever (AS security)
carver 1 is offline   Reply With Quote
Old 07-17-2015, 03:12 PM   #7
Rivet Master
 
2007 25' Safari FB SE
Suburbia , Sunny So Cal
Join Date: Jun 2006
Posts: 3,756
I like 3:73's in my 4X4's. On a straight street truck either is just fine with a Powerstroke. It wouldn't make a difference to me.
__________________
I'd rather be boon docking in the desert.

WBCCI 6731 FCU
AIR# 13896
CA 4
Goin camping is offline   Reply With Quote
Old 07-17-2015, 09:05 PM   #8
Full time Airstreamer
 
SCOTTinNJ's Avatar
 
2014 30' FB FC Bunk
Anywhere , USA Living.Somewhere.Yonder
Join Date: Jan 2014
Posts: 1,161
Quote:
Originally Posted by DKB_SATX View Post
I just happened upon an article about Ford's commercial vehicles... the F650 and F750 also use the 6.7L as one of their powerplant options... and in the hottest of the 3 tunes it's putting out 330hp and 725 lb-ft. of torque. This in a truck that's going to do WAY more work than probably 95% of F250s on a day-to-day basis. It speaks to what ludicrous overkill the numbers battle between the big 3 has become... the F250 is tuned for 440 hp and 860 lb-ft of torque. I wonder how much longer they'd last tuned like an F750.
I agree and would gladly take any of the F650/750 versions if it meant better gas mileage (i assume longevity is a given). Here they are.

270 horsepower/675 lb.-ft. torque
300 horsepower /700 lb.-ft. torque
330 horsepower/725 lb.-ft. torque
__________________
@living.somewhere.yonder | Instagram
SCOTTinNJ is online now   Reply With Quote
Old 07-17-2015, 09:24 PM   #9
Rivet Master
 
pappy19's Avatar
 
2002 30' Classic S/O
Garden Valley , Idaho
Join Date: Jul 2010
Posts: 1,418
You won't be disappointed in the 3.73, but if I was looking at a new 6.7, I would go with the 3.55 if I was in the mountains. Otherwise, the higher ratio (lower number) will be fine.
__________________
2008 F-250 4X4 Lariat V-10
2002 Airstream Classic 30' w/SO #2074
2007 Kubota 900 RTV
1996 Ford Bronco
2007 Lincoln LT
pappy19 is offline   Reply With Quote
Old 07-17-2015, 10:14 PM   #10
gpt
4 Rivet Member
 
2014 25' FB Flying Cloud
sequim , Washington
Join Date: Dec 2014
Posts: 296
3.55 is in my f350. works just great and a good pairing with all of that torque and hp.
__________________
gpt is offline   Reply With Quote
Old 07-19-2015, 05:16 PM   #11
2 Rivet Member
 
2017 30' International
Woodland , California
Join Date: Jul 2014
Posts: 27
3.31 or 3.73

I have a 2015 F250 6.7 with the 3.31 ratio and I like any advantage I can get for maximizing fuel economy. Towing an AS25FB is easy with this truck. Here in California with the Sierras to climb, I find that I just keep the tranny in 5th at 50-55mph on the climbs and the engine revs nice and easy, 1600-1800 RPM, just above peak torque. As an old trucker, letting that engine work just above peak torque let's it run easy on 6% grades at altitude which may not be necessary, but makes me happy.
__________________
Jmacd is offline   Reply With Quote
Old 07-20-2015, 08:00 AM   #12
TinCan
 
graysailor's Avatar

 
2016 30' Classic
Apache Junction , Arizona
Join Date: Aug 2011
Posts: 798
As an old trucker myself I loved my Cat's. The lower the RPM the better they pulled and with decent fuel economy. Hopping the same will be true with my 2016 F250 which is on order. Big changes coming with the 2017's but just can't wait another year.
__________________

__________________
TinCan
graysailor is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to set the on/off temperature differential on Dometic Furnace warmrain Furnaces, Heaters, Fireplaces & Air Conditioning 16 01-13-2014 09:59 AM
Differential maintenance tpi Tow Vehicles 10 07-18-2011 04:44 PM
Rear Differential Problem?? Help! FLYNCLD Tow Vehicles 31 04-19-2010 12:04 PM
Temperature Differential Expected JimGolden Furnaces, Heaters, Fireplaces & Air Conditioning 6 11-28-2005 11:48 AM
split differential or locking differential cindy foxx Tow Vehicles 6 01-22-2003 08:48 PM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 11:38 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.