Good afternoon, folks,
I got burned with a smoker back in the mid 1980's and have been hesitant to come back. I am currently pulling my 5er and my enclosed gooseneck with a 6.2 gasser SRW. It has the 3.73 gears in it...not the best for towing.
I am thinking about ordering a new SD DRW 2wd with the 6.7 PSD.
Both my trailers are rated at 18000 GVW, what would be the best ratio to order? 3.73's?? 3.55? Fuel mileage will be what it will be with what ever ratio I go with. The truck will be mainly a puller. Not a daily driver.

 

I'd go down to at least 3.73. Personally I'd get 4.10s to be pulling 18,000 lbs but I don't know if that's still available or not.

 

Next step from 3.73 is 4.30

 

My Mobile Suites is 16 to 17,000 lbs loaded, maybe a little more with full tanks so it's comparable. I've towed it with an F250 7.3L SRW 4.10 axle, a 6.4L F350 DRW 4.30 axle and my 6.7L DRW 3.73 axle. They all were OK.

The 250 was pushed around in the wind and in mountains and on curves. But I got 10 to 11 MPG and I loved the truck. If I were younger or poorer I could have kept using it.

The 6.4L was a great tow vehicle. The 4.30 axle is awesome. Once I got it deleted and tuned the 6.4L was giving me almost as good MPGs as the 7.3L. I swear that truck could have pulled my 5er up a pine tree. A drunk old woman hit me last winter and it was totaled.

I've got 9000 miles on the new truck, a lot of it towing. I only drive it on trips. There is no noticeable difference from the 6.4L on the highway except for fuel mileage (around 9 over all). Going through the mountains of western NC I could feel the difference from the 4.30 axle. But, the truck has done fine and the difference is minor.

And keep in mind, the 4.10 axle was paired with a 4 speed tranny, the 6.4 with a 5 speed and the 6.7L with a six speed. That helps some and the tranny is very helpful going up and mountains.

Hope this helps and if you have any questions just ask.

 

I guess I was concerned that the 4.30 might be a little too deep for the 6.7 PSD with the torque that it puts out, but maybe not?????? If you were ordering, is that what you would get? I am full of questions!! Any trouble with the 6.7 emissions stuff?????
Thanks in advance.

 

I'd get 3.73's myself. Best all around gear set for a SRW/DRW with the diesel. I have close to 14K towing miles on mine.


Cross Country and throughout the Rockies. Gears are just about right for me.

 

OK, thanks. That is kind of what I was "thinking"; but my "thinking" has gotten me into trouble in the past too many times!!!!!

 

big thing that helps with the 6.7 is the manual mode for the tranny. That will do the best when towing.

 

Yeah, I use the "M" position with the 6.2 gasser quite a bit too, just gotta decide now what I want to do. Will probably definately order a dually. 6.7 PSD with 3.73's or 6.2 gasser with 4.30's. And that I gotta do for myself!!!
And thanks for the advice.

 

I just placed on order a F-350 Dually. Only two choices on the rear end ratios: 3.73 and 4.30. If you choose the "Wide Track" front end....Only the 4.30 is available. I choose the 3.73 limited slip.

My current truck is a 2011 F-350 SRW with 3.55 rear end. I tow a 42 ft 5th wheel that hits the scales at 17300 lbs gross. triple axle. I live it montana, rockies and high winds and flat land.......truck does very well.

So, I figure the 3.73 will be plenty of power and better on fuel than the 4.30.

Have Fun !!

 

It's a tough call and depends what you want to do. Kinda like 4 wheel drive. I almost never use it except to test it. The 6.4L was 2 wheel drive and only once in 5 years did I wish it was 4 WD. The 4.30 power is nice to have if draging trailers up really steep secondary roads, but we were in western north carolina this summer and the 6.7L was fine.

I think if it was for me I'd go with the 3.73 and save the fuel costs. But I'm over 70 now and don't go in to the hard to reach camp areas any more.

The 6.7 technolgy is a good bit superior to the 6.4L. The regens are almost non-events. Using the DEF seems to help the emissions a lot. I track the regens out of habit but if I didn't I could just drive the truck and pay no attention. It's funny, every now and then I drop in back at the 6.4L forum and they are talking turbos, deletes, broken trucks and all sorts of mayhem. Over here it's mostly pictures of trucks and camp sites. Doesn't seem to be much going wrong with the 6.7s.

 

3.73 with mine (also a 4x4) and dragging a 17k 13' tall fifth wheel toy hauler... This truck doe not break a sweat dragging that trailer at 65 mph in Tow-haul mode with the exhaust brake set to "on".. Comes to a long hill, it doesn't play games shifting the transmission down and making all sorts of fuss. The turbo gauge climbs a little and the truck never skips a beat climbing the hill.. Coming back down the other side it just starts applying the EB and it maintains speed.. Climbing all across the rolling hills of Nebraska, Iowa and Minnesota it was perfect. I've not done mountains with it yet - that's next year..
Oh and fuel economy was almost 18 unloaded and 8.5+ loaded.
Glad I made the choice I did. In my opinion, you won't need those 4:30 hears unless you are pulling more than 20k and even then, the gearing of the transmission is such that it would probably move a mountain with 3.73's if you could figure out how to hitch up to it..

 

Yup; quite familiar with your neck of the woods! Western ND here and generally pull across MT on 94/90 to Whitehall, then down to Dillon and catch 15 there and south through ID, UT, NV, and into AZ. My 6.2 gasser doesn't do "bad", I just don't get in a hurry and just figure the 6.7 will do "better" and a dually will definitely be a plus.
Thanks for the input.

 

Ratios are a tough call, your choices are between 3.73 and 4:30 as has been pointed out. For me, I was going to order a new F-450 with 4:30s. For me, pulling in the mountains is the rule, not the exception.
I'd say, how close to that 18K are you going to be the majority of the time, how high & wide is the load and how much do value performance in the mountains. At highway speeds, wind load is more of a factor than weight most of the time, until you hit the hills. The 4:30s really shine in the mountains. Too bad 4:10s aren't available, they're probably optimal for those of us pulling these kind of loads.
2wd? I haven't seen one of those on the lot in years!

 

As an old retarded, I mean retired, trucker; I have these thing figured out.
Just trying to get some real world input from those running the 6.7 PSD where the real meat of the torque curve is going to come into play. One thing I don't do is get in a hurry when pulling. I could care less if I am the last one up the hill.
Thanks