F350 SRW w/3.55 Rear End

[av2pilot]

I've gone from a 99 3/4 ton dodge diesel to a 2006 1 ton dodge diesel and I'm looking at a 1 ton Ford Super Duty diesel with a 3.55 rear end. Everything seems to point that I'll be fine, but I know there are some of you out there with maybe this exact setup that could provide me insight...I tow a 3400

[Mudchief]

I am towing a 3400 and it does a super job.

[BB_TX]

I have a little lighter 3075RL. But my 2012 6.7 F350 tows it great over Colorado mountain passes. On relatively flat highways it stays in OD most of the time turning under 2,000 rpm at 65-70 mph. So much power the 3:55 works fine.

[1retired06]

That is a good differential, have run in several trucks, no complaints

[av2pilot]

Thanks for the responses......does the 2015 ford have a exhaust brake and transmission cooler.

[1retired06]

Yes to the transmission cooler and it has both engine exhaust and tow haul braking. Thought 3.73 or 4.30 were the options

[Artemus Gordon]

2013-14 also have both. Exhaust brake is excellent. It's used by tapping the brake. 15s have switch because many drivers could not understand how the system worked. Lol

[JandC]

When I purchased my truck I was suspect of the 3:55. Started towing our 3400RL that we had then and it was great, then with a little heavier Montana that we have now it was also good.

I certain circumstances, for example a lot of rolling hills where I may only be going 55 - 58mph I generally keep it in 5th gear so there is no downshifting. But for most interstate pulling I keep cruise set between 62 and 65 in "D" and just let-the-big-dog-eat!

[waynemoore]

I have a 2015 F350 with 3.55 rear end and pull my 3582RL at about 14,500 lbs with no problem at all. It's a great strong truck.

[Charli]

Didn't think the Ford got the exhaust brake till '15. Our '11 just has the tow haul transmission braking. Lost the trailer brakes in April coming from Vale to Denver and would have given anything for my '08 Cummins engine brake. Made it but had to keep the truck in 2nd gear so I wouldn't be a run away on the long downhill runs.

[DuneBuggyBuilder]

While the rear end ratio is an important number, you also have to consider the transmission gear ratios. Combine the short first and second gear ratios with a 3.55 rear end and you have a vehicle that will beat a Corvette off the line (if you can keep the rear tires from spinning). Then the high torque of the 6.7L diesel is able to effectively utilize the taller fifth and sixth gears and maintain low RPMS at highway speed. I have over 25K miles on a 15,500 lb. Montana, up and over the mountains of the west, towing with a Ford with a 3.55 rear end.


Ford - 6R140 Gear Ratios:
First - 3.97:1
Second - 2.32:1
Third - 1.52:1
Fourth - 1.15:1
Fifth - 0.86:1
Sixth - 0.67:1

Read more: http://www.trucktrend.com/features/1...#ixzz3eOl552tg



Chevy/GMC _ Allison 1000 Ratios
1st - 3.094
2nd - 1.809
3rd - 1.406
4th -1.00
5th - 0.711
6th - 0.614
Source: http://duramaxhub.com/allison-transmission.html

Dodge 68RFE Transmission Ratios
1st - 3.23 : 1
2nd - 1.84 : 1
3rd - 1.41 : 1
4th - 1.00 : 1
5th - 0.82 : 1
6th - 0.63 : 1
Source: http://www.dieselhub.com/trans/68RFE.html

[WeBeFulltime]

I guess I am the odd ball (again) but my 2012 F350 has the 3.31 rear end and is a 4 X 2. We are full timers and our 3585SA Cat Scales @ 14,500 and the Super Duty does a GREAT job.