Diesel Towing Experience

[donreitz]

Although I don't want to start a "diesel vs. gas" thread, I thought that our experience traveling around the Rockies with our '06 Silverado D/A was sufficiently impressive to generate a comment here. We purchased the truck last year when we decided that a dedicated tow vehicle was justified (principally because the kids flew the coop and we didn't need a combination family car/tow vehicle anymore). The diesel was impressive right from the start, but traveling around the flat Midwest hardly tasked its abilities. This year we planned a trip out West over ground we've traveled before, so we could directly compare our gas and diesel engine towing experiences.

Well, there's no comparison. The diesel blew up hills like nobody's business compared to our previous Tahoe and Suburbans. What was most noticeable was the ease with which we traveled the Rockies: set a reasonable speed and you'll go up at that speed, period. Whereas I would previously be stuck in the far right lane, now I can move into other lanes without fear of backing up traffic. It wasn't a whole lot more challenging than traveling on the flats.

Even more impressive, though, is the Allison transmission with "grade breaking" (I assume other manufacturers offer something similar). The idea behind grade breaking is that the transmission will do its best to maintain a constant speed downhill when towing. In tow mode, when going downhill tap your brakes and the transmission downshifts providing engine breaking. If you speed up, tap the brakes again and the transmission will downshift once more. I could maintain a reasonable 60 mph downhill on the steepest grades on I-70 west of Denver while barely using the brakes. Amazing, and it sure made for an easy drive. Mileage in the Rockies was in the 12s and 13s.

This isn't to say that towing with a diesel is the only way to go (we managed quite well for years without one). But if you plan on towing in some of the more topographically challenging areas of the country you could do worse than doing it with a diesel.
Don

[rich2500]

I know what your saying Don,makes me think back to when we used to tow our 22ft. nash with our Durango,I would drive several miles out of my way to avoid big hills that I knew the durango would struggle on,after about 6 trips like that I decided I was getting a diesel and done,now I look forward to pulling big hills just to give my truck a workout.

[kanyonkitty]

Isn't all that power wonderful Hum, don't think I've needed all of mine (YET!) Note to self: plan more trips

[nickster60]

I would agree I love the diesels. I have stumbled on to gas truck that is worthy of any diesel. I came across a Dodge with a v10 I got a really good deal on it. And if I may say " HOLY CRAP" this thing is beast. Not in a diesel kind of way, more like a hot rod kind of way. It has tons of power and tows really well. 60 mph 1550 rpm with the overdrive on. When I first got it I was in front of the house and stomped on it it smoked the tires for about 50 ft. It does have a draw back it only get 10.5 mpg towing. But boy is it fun.

[Tweety]

We looked at the Toyota Tundra, but ended up with the Sierra D/A, and boy are we happy Towing a QUE we can't get it to downshift even on big mountains! AND we get 16.5 mpg around town or towing and just got 20.5 highway not towing.

[PTHutch]

Hi Don,

Thanks for sharing, it’s niece to hear stories like that.

How many miles do you have on your truck?

I have 17,000+ miles on our 2006 Sierra D/A and we're averaging 11 mpg towing. I installed a K&N air filter in May, but have seen no improvement in gas mileage. I track the gas mileage at every fill-up. I wish I could average 12 – 13 mpg towing. It must be the added weight and drag of our T-280SR compared to your T-2499 that is making the difference. I’m guessing our trailer is probably 2,000 lbs heavier than your trailer when loaded and since the slide rooms site a few inches higher, that has to add some to the wind drag.

We went out west with our T-2670 pulled by a Ford E-150 Conversion Van w/ the 5.4L engine / 3.55 gears. And that was petal to the metal to get up the mountains and 2nd gear to get down – white knuckle driving at it’s best . I can’t wait to take our new Sunline and tow vehicle out west. I’m anticipating I’ll have the same enjoyment as you.

We’ve towed through the mountains of PA (i.e., only big hills compared to out west), but have experienced the same pleasure as you. Heading down a mountain where the truck speed was 45 mph, the grade braking feature of the Allison maintained that speed without touching the brakes, even with our 8,000 lb trailer pushing behind. Love it!

Again, thanks for sharing your experiences.
Hutch

[Sunline Fan]

Hutch,

From what I hear, you should see significant improvement in mileage once you get some more miles racked up (like 50,000).

Jon

[264SRinPA]

The only bad thing I have found with a diesel is I have to remind myself to slow down when towing.

[donreitz]

Hutch, we just went over 16,000 miles with our trip out West. From what I've seen of others' storage compartments, I think we travel relatively lightly. Additionally, I'm pretty conservative with the gas pedal: generally no more that 65 mph on the interstates and I keep it at 60 or under on the hills (of course before the diesel I couldn't even do 60 on the hills). Our worse towing mileage was in Kansas fighting crosswinds (in the low 10s) and our best was in the 12s. Interestingly, we got in the 12s both driving on flat interstates in calm weather and on I-70 through the Rockies. These figures are whole-tank averages (a 45 gallon tank) so I assume the "good" mileage obtained in the Rockies is due to going down as much as going up.

Surprisingly, the tonneau cover I recently purchased has improved my non-towing mileage. Whereas before I would get in the 19s driving unloaded at 65 mph on I-69 (this goes down in the winter), I now get in the low 21s. These figures come from the mileage calculator function of the Driver's Information Center. It consistently reads about 1 mpg low compared to doing the calculation by hand.

I mentioned the oversized fuel tank. After traveling in remote areas in the Four-Corners area, I have to say that a big tank is worth every penny for the peace of mind it permits With judicious fill ups, we were able to travel to remote sections of Utah knowing we had more than enough fuel to sightsee and get back to civilization.
Don

[PTHutch]

Originally Posted by donreitz

I mentioned the oversized fuel tank.

Don,

It sounds like you had a Transfer Flow replacement tank installed in your truck.

After it was installed, have you seen any difference in the information displayed on the DIC or gas gauge?
I've heard that the gas gauge’s low fuel warning light comes on when there's still 10 gallons remaining and that the DIC’s remaining range / miles you can travel information no longer works (or is still based on the original tank size), is that true?

I’ve been looking at getting one installed in our truck.

Thanks for the info.
Hutch

[Sunline Fan]

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[donreitz]

The Transfer Flow is a steel tank that replaces the stock plastic one. I can't tell you about the low fuel warning light as I haven't gotten much below 1/4 full. Our traveling rule is to start looking for stations when half empty. That's about 250 miles of towing, which is long enough without a stop anyway.

The miles remaining function of the DIC does not work. It obviously assumes the tank is still stock (26 gallons if I recall correctly). I don't miss it. The gas gauge works fine.

I think the oversized tank is like air conditioning: once you have it you can't live without it. It certainly makes it much easier to travel to remote locations where diesel may or may not be available (although I am surprised how many stations, even in small towns, have diesel). In my own limited experience, the problem is not so much finding diesel in out-of-the-way places, but finding a station big enough to accommodate your trailer. Of course, as a result of having that big tank, I just had my first $100 fill up. Ouch.
Don

[PTHutch]

Hi Don,

Thanks for the information. It helps a lot.

Originally Posted by donreitz

The miles remaining function of the DIC does not work. It obviously assumes the tank is still stock (26 gallons if I recall correctly). I don't miss it. The gas gauge works fine.

What about the other information on the DIC like gallons used and mpg - do those still work ok?

Originally Posted by donreitz

I think the oversized tank is like air conditioning: once you have it you can't live without it.

I agree, I think it gives great piece of mind whle traveling.
Bit, I'm still trying to convince Mary it's a good investment / purchase.

Originally Posted by donreitz

Our traveling rule is to start looking for stations when half empty. That's about 250 miles of towing, which is long enough without a stop anyway.

We do the same thing, but w/ the 26 gallon tank, ½ tank is only about 130 miles of driving.
On extended trips seeing the country we try to limit travel days to 200-250 miles / day.

Originally Posted by donreitz

I am surprised how many stations, even in small towns, have diesel.

That's good to know. When we bought the diesel, finding gas stations with diesel was my biggest worry. But no problem so far, but we travel a lot of expressways.

Originally Posted by donreitz

I just had my first $100 fill up. Ouch.

Ouch is right .
But if you look at it this way, there's no difference than filling up 2 times @ $50+ each time or 1 time at $100 - it's all the same - but there's still that sticker shock

Hutch

[nickster60]

I used the Dodge to pull on of our landscaping rigs. That was a painful Truck 35 gallons, 3 mowers 17 gallons. 4 5 gallon gas cans. It came to about $225.00. It has painful for all except the oil companies. Has the fuel prices changed your travel plans? I have always wondered how it affects the rest of the RV community.

[PTHutch]

Originally Posted by nickster60

Has the fuel prices changed your travel plans?

Not at all for us. And I don't think it will in the future either.

I would rather sacrifice on other things so we have more $ to cover the increased cost of camping, than to change how, when, or where we camp.

[Mark]

I just heard that the newest prediction is for $100/barrel oil, so look for spiking in the next two months.

This time Turkey is being blamed for the "tension". IF you want to get sad, GooGle the price of oil per barrel since 2001.........

[donreitz]

As far as I can tell, the rest of the DIC works fine with the large tank. The DIC's mileage figure is almost invariably one mpg lower than the mpg figured by hand. From what I've heard on various forums, this is not unusual.

Update: a 180 mile run on I-69 today netted me 22.3 mpg (unloaded, calm weather). The Extang tonneau cover is responsible for this. Non-tonneau mileage averaged 19.8.

Hutch, you're right of course about there being no real difference between filling up a little several times and filling up a lot once. Nevertheless, it's still startling to get that $100 receipt. It helps that we do the credit card swipe thing at the fuel pump so we never actually see the money we're spending.

Has the price of gas reduced our travel? No. Will it in the future? Probably not unless fuel prices go postal. As Hutch states, we'll economize elsewhere if necessary. Many of the best times we've had have been on the road and that's worth alot. As we gradually spend more time traveling we're actually helping keep our cost of living down: we spend more time heating and cooling a very small area and less time doing the same in our much larger home. Also, unlike the heavily travel-dependent vacationing we do now, as fuel prices rise we're more likely to stay put for awhile at various locations and use less fuel as a consequence.

Excellent discussion.
Don

[MACK C-85]

The other fun time with a Diesel is oil change time....13 quarts!! OUCH

[Sunline Fan]

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[MACK C-85]

Yeah, I know......I've helped service Cummins and 60 Series Detroits in our Fire Apparatus...you start to wonder where it's all coming from