I have an 87 f-250 6.9 with a c6 and a dne2 overdrive and 4.10's. I was wondering how you guys with 3.55's manage with towing heavy trailers at highway speeds. I have a 32 foot travel trailer that weights about 8500 pounds loaded and I can just do 60 if i'm lucky, but i'm screaming because i can't ust the overdrive. I just got this truck and I was thinking about going to 3.55's to keep the revs down, but I don't think that I've got the power to do so. It has a three inch exhaust and I think the ip is turned up because it smokes a little on heavy acceleration like people say they do when it's turned up. 60 is not fast enough I like to do 70 towing. I know it's not gonna be like my 96 psd and I don't expext it to be. Also could run in second with the overdrive engaged for lond peroids of time if I do go with 3.55's and don't have the ***** for third w/o od? Thanks guys

 

I tow more weight, but it has nowhere near the frontal area of a travel trailer.
Both the mini excavator and skid steer I usually pull weigh very close to 10,000 pounds plus the trailer weight.

After years of over the road truck driving, I know what the midwest wind can do to towing speeds when you have a large frontal area.

Is your trailer a fiver or a tag along?

Look at the aerodynamics of your rig, that is where your answer will be.
A turbo may have to enter the equation also.

 

Yea Dave, It's kinda like towing a brick wall. It's a tag along. I don't expect to be able to pull grades at speed. Just want to be able to do it on the flats. I also do alot of highway driving when i'm empty that's why I'm looking into gears to keep thae revs down and get some economy back, but I don't want to scrafice towing ability.This turck is a way for me to get some bills paid off. So I'm not gonna to a turbo or any big buck upgrade, but I was thinking about looking into duel 3 inch exhaust if I can do it reasonable enough. Want to do an intake mod and a few other things. my air cleaner lid is aftermarket and I can't cut the soupbowl off. It'a a ray-well "high performance" lid. I would ask you for your numbers, but I know your truck is a fire breather. Thanks for the info Dale

 

Do you have a topper on the truck bed?
How about any wind deflectors on the truck or trailer?

When I was an over the road driver back in the 70's and the oil crisis crap all started, there were several studies done on the the big rigs and wind resistance from the lack of aerodynamics at that time.

The results were not exactly what everyone expected.
Yes it takes a large amount of power to shove a big rig through the air, they have very large frontal areas.
What the surprise was though was that only took something like 35% of the power expended.( I can not remember the exact numbers, that was way to many moons ago.) Where the big power expendature was happening was between the cab and trailer and behind the trailer. Those areas were sucking up over 50% of the power needed to roll down a level road. The truck punches a hole in the air, than after it passes it drags that hole down the road with the truck. Dragging the hole was responsible for most of the power consumption. Big rigs of the day were averaging 3.5 to 4 MPG.
Several companies, Beacon Van Lines was one if I remember right started experimenting with aerodynamics big time.
Farings on the tractor to smooth the air flow around the hole between the tractor and trailer.
Side skirts on the tractor.
Side skirts under the trailer.
Big boat tail farings on the rear of the trailer.
Everyone thought they were nuts, but it doubled the fuel mileage.
The driver also reported that the truck ran the same speed much easier after the aerodynamics were installed. (This part says that the truck had enough extra power to run much faster if he so desired.)
Shortly after that, you started seeing all kinds of wings and fairings that could be bolted to your rig to help with the aerodynamics.
Today some of those same things are built in from the factory, several more like the sloped hood on a conventional tractor were also introduced since they had to be engineered in at the design level.

I can also tell you from experience that a head wind is hard to fight, but when the wind is from either 45 degrees left or right of dead ahead it is even harder.

Do take a serious look at something like a wing or fairings that will make your rig more aerodynamic, you will either be able to increase you MPG or speed, possibly both.

 

I have an 1989 super duty 7.3 non turbo dually with 5:13 rear gears, ZF 5 speed standard. I can run in over drive most of the time and hit 65 to 70mph. My 35 foot 5th wheel trailer is a toy hauler and with two cycles, water and all the trailer weighs in at 11,300. The low gears get you out of the hole and the low gears take the strain off the transmission. Then you can run in over drive, but don't look for much over 70 mph, but why would you want to with all that weight.