Gas Mileage towing a fifth wheel

Thanks Tom and Marti, you have made some good points. Having "home" around you sure beats staying in a motel. We have joined the Good Sam club and hope to take advantage of the discounts. Looking forward to retirement and traveling in the 5th wheel.

Thanks Al for the encouraging news. Glad to learn that the 7.3 liter Ford is considered good. As we are new to all the terminology and have to learn about exhaust brakes, brake controllers and transmission coolers. If you are going to pull a 5th wheel, I guess you just have to bit the bullet and pay for fuel costs.

Thanks Hoeboe for the information. Glad to hear that a diesel gets better mileage. After purchasing new tires for our truck, we will give it a good test drive to see what non towing mileage will be.

Thanks Shaffjc for the information. Our 2001 ford SD 7.3 diesel only has about 40K miles on it. Bought is used and had to put a transmission in it later. Needing new tires, we will then give it a good test drive to determine non towing mileage. I guess you just have to bit the bullet and pay for the fuel costs.
 
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lwmcguir

Well-known member
One of the biggest advantages of the newer trucks is the 5 or 6 speed transmission. With all the new ones coming in now with 6 speeds it will really ad a degree of comfort when climbing grades. Our old ones used to change 900 rpm between gears. Sure don't miss that one bit.
 

Birchwood

Well-known member
We have an 07 GMC 3500 diesel (6 speed)that hauls our Landmark Pinehurst (15000 lb range).Get 10 to 11 mpg (CDN) hauling and around 20 mpg unloaded.
The grade braking on the GMC saves a lot of brake pad.Seems most of the diesels have ample power hauling up grades but going down the other side of the mountain is where you really need the smart transmission.
 

back2nature

Well-known member
Hi bikerchick,

We have the same truck. The 7.3 engine is a great engine. It can handle a a lot. We do have the short bed, SRW, not sure what you have. We have added air bags, trans cooler and The Edge Evolution (Performance Programmer). We typically get about 18-19 mpg when not towing. But towing the BH 3670RL, we get about 11-12 mpg on the flat lands and going uphill it goes down from there. Actually, last month we were coming out of Death Valley through some very steep mountains, with a 10% grade (we WILL NOT do that again, brakes got hot, it was scary) and it was showing down to 3.7 mpg. Yikes! The Edge saved our butt, because we could see it was starting to heat up and we pulled over to cool the engine and the brakes. We found that dropping down one gear (and going slower, 30 mph) really helped keeping the engine cooler. I would definitely suggest getting a performance monitor if you are going to pull one of the heavier trailers. So glad we had it. Saved us for doing any damage.

Like so many here have stated, there are so many variables. Which rv model you choose, how heavy you pack it, whether you are going up or down a hill, or not. That being said, the 7.3 will pull them no problem. Just watch the hills. Our mechanic says it's one of the better engines Ford made. Stick with it.
 

rumaco

US Army Retired (CW4)
Rotten!!!!!! If you think 5ers and good gas mileage go together you better rethink your purchase! Simple as that!!!!!!!
 

rumaco

US Army Retired (CW4)
Actually the best towing engine ever made was the true 7.3 Powerstroke which ended it's rule in 2000 and gave way to the absolute crap as the 2003 (most worthless powerstroke ever made) and future years. Want a real deisel get a cummins and hook it up with an Allison tranny on a Ford chassis. WOW now there is a rig!!!!!!!!!!!!!!!!
 

rumaco

US Army Retired (CW4)
Buy the way, the reason you changed your transmission (as I have also) is the Ford junk tranny which is known as the R4100.
 

6.7powerstroke

Active Member
The 4R100 is a great transmission. The biggest problem on the 7.3s was the dinky tranny cooler that Ford put on the truck. One of the best upgrades you can do is to add a newer 6.0 tranny cooler in place of your old 7.3 cooler. The 7.3 cooler has 7 rows for cooling while the 6.0 cooler has 31 rows. It will save your tranny. you should also run a tranny gauge if you are towing. Heat kills. Never let your tranny get over 225 degrees or things start failing.

If your 4R100 dies, DO NOT replace it with anything other than a Brian's Truck Shop (BTS) or John Wood transmission. These will run you more than a stock Ford one but they are bullet proof. BTS will dare you to try and break it and it pretty much has a lifetime warranty. BTS is in Arkansas and John Wood is in California. It will cost you 3400-4000 for one of these but it will be the last transmission you will ever buy.
 

caissiel

Senior Member
I pulled a 33ft 5th 12K lbs 5th wheel with a GM 6.5L for 9 years and was very satisfied with the TV and took good care of it. The truck was very thirsty and only could get 9 MPG at best of times. But once the warranty was over after 5 years I modified the turbo controls and got as much as 20MPG empty and 10MPG towing the same trailer.
I traded for the F250 and got the same mileage as the modified GM and was very satisfied with the pulling. But the truck slowed down in the hills, and had to shift on high gear. I then used a Hypertech E-Con and now it mowes the hills on overdrive and the mileage realy increased to a surprising 12MPG.
Then we traded the trailer to a heavier and longer Big Country and to my surprise it actualy pulls easier then the old trailer. We have reached as high as 16MPG on flat highways of Florida. And the last trip I we did better then 12MPG average coming down to Florida a 2000 mile trip.

I use the Scangauge II and always keep a watch on the torque readings while towing. These readings are proportional the the fuel consumed. The GM could be keeped at around 85% value and I would be able to get 10MPG and the F250 is at 55% and getting 12MPG and if the torque increases it realy takes the MPG down fast. So my conclusion is that the F250 is not loaded at all, if the GM lasted 9 years.

While driving with a side wind the MPG drops down a lot so I slow down to 55MPG and it seam to level off at normal consumption that I usualy get while driving at 65MPH. The side wind has a greater effect on mileage then any head wind and I see it on the scangauge. Head wind has only 8 feet by 4 to 6 ft to affect the mileage, while side wind affect 12 ft x 38 ft long on my unit.

I say it again that lenght of trailer only effect drivability in side winds and weight usualy effect power in the hills, and with the experience with this BC makes me feel that this trailer is great at any condition as long as driving condition taken into considaration.

My friend had a long light TT trailer and pulling it with 2500 GM and one day he went to do a street turn and the wind took the trailer and overturned it sideways in the intersection. He was very lucky he was driving the heavy GM. So light trailers are only nice but not realy practical or safe. They are like a billboard waiting for the wind to push them
 

lwmcguir

Well-known member
Actually the best towing engine ever made was the true 7.3 Powerstroke which ended it's rule in 2000 and gave way to the absolute crap as the 2003 (most worthless powerstroke ever made) and future years. Want a real deisel get a cummins and hook it up with an Allison tranny on a Ford chassis. WOW now there is a rig!!!!!!!!!!!!!!!!

A guess you know you can order the F550 and up series with a Cat, Cummins, or Ford engine? Nothing wrong with the new 6.7 either.
 

caissiel

Senior Member
Cat will or has stop making road engines due to the Diesel engines CARB requirements.
The Internationasl Max 365 With over 1,000,000 engine out on the roads and Ford's equivalent 6.0L Will go out as an extremely well suited engine as well.
The fixe for this engine has been found and once the warranty is over, owners can treat them as International engines.
The Ford delima is the wrong coolant being used in the engine and we are slowly converting the 6.0L followers to do the switch.
The truck has A great transmissions and cooling system that makes them great haulers.
I have mine set at 439HP and surely feel confident it is right for my needs.
That is after switching from the gold C..P to ELC Cat EC-1 coolant.
 

lwmcguir

Well-known member
We ran the 6.0 engine for a lot of miles as well and the coolant was the only problem of any magnitude we had. Plenty of horsepower and the transmission was a nice step up the the 4 speed overdrive. Much better mileage as well. They are probably the best kept secret for the price out there right now if you take care of the coolant issue.
 

TandT

Founding Utah Chapter Leaders-Retired
Hi bikerchick,

We have the same truck. The 7.3 engine is a great engine. It can handle a a lot. We do have the short bed, SRW, not sure what you have. We have added air bags, trans cooler and The Edge Evolution (Performance Programmer). We typically get about 18-19 mpg when not towing. But towing the BH 3670RL, we get about 11-12 mpg on the flat lands and going uphill it goes down from there. Actually, last month we were coming out of Death Valley through some very steep mountains, with a 10% grade (we WILL NOT do that again, brakes got hot, it was scary) and it was showing down to 3.7 mpg. Yikes! The Edge saved our butt, because we could see it was starting to heat up and we pulled over to cool the engine and the brakes. We found that dropping down one gear (and going slower, 30 mph) really helped keeping the engine cooler. I would definitely suggest getting a performance monitor if you are going to pull one of the heavier trailers. So glad we had it. Saved us for doing any damage.

Like so many here have stated, there are so many variables. Which rv model you choose, how heavy you pack it, whether you are going up or down a hill, or not. That being said, the 7.3 will pull them no problem. Just watch the hills. Our mechanic says it's one of the better engines Ford made. Stick with it.

I know the hill you mean. Towne Pass, out of Stovepipe Wells going west. I've white knuckled that one myself, with my old 10k lb. SOB. I even have a Banks programmer & exhaust brake and it's still hairy. I made a promise to myself. With the new BH I'm going around until further notice.
 

caissiel

Senior Member
I don't want to start a new thread but I was realy surprise today towing our BC with the F250.
We travelled 2000 miles coming home from Florida to new Brunswick, Canada. We arrived accross the border and visited with my wife's mother for the weekend.
All along the trip the fuel mileage was excellent and averaged over 13MPG US. The truck has been pulling the RV for 2 years with no problem and the RV feels great while towing in all sort of terrain. I have towed this unit with the truck programed all the time, and it has performed well.

When we stoped the FICM module needed repairs so I reprogramed the truck to stock. The repairs were done and I proceded to take the unit home. I left the truck programed stock and drove 130 miles. Well it felt like the trailer was awfull heavy and the fuel mileage just tanked, I barely was able to keep it above 9 MPG and had to shift at most hills and lost speed in the hills. As soon as I came to a hill the torque climbed to 100% and I had noting extra to top the hill. An other thing I noticed is that the coolant temperature was climbing all the time.

I realy felt bad seeing the fuel gauge go down so fast, so I stopped and reprogramed the truck using the Max Energy level 3. Well the remainder of the trip was so different, the truck hardly felt the weight in tow and the fuel readings instantly went up to 14MPG again and every hill was done on overdrive without even using all the torque.

Since I never towed the BC before on stock, I was well surprice at the weight the trailer puts on the truck.

I have been towing for the past 4 years while programed, and in no way will I attempt to tow on stock program again. Even Level 1 is miles ahead of the stock programing.
 

wonka

Active Member
My husband and I are seriously considering purchasing a Heartland fifthwheel in the near future. With gas prices rising, we are trying to get an idea what kind of gas mileage we will get. We have a 2001 Ford F250 diesel 7.3 liter engine. We are looking for a fifth wheel in the 10,500lb dry weight range. Some folks have said there is not much difference with or without a trailer unless you are climbing mountains.

Any information and experiences with gas mileage will be greatly appreciated for these two newbie's.:confused:

bikerchick

We use to own a 2001 f350 powerstroke, it got 12, uphill, downhill, empty, or pulling 18,000 #'s, not sure how yours is, but ours never changed in the 70000 k's we had it. Our '03 Duramax pulled 22 - 25 empty, and 15-17 tugging. Our '11 so far is no where as good.
 
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