towing with Chevy Express Van

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ahiburger

Member
Joined
Apr 3, 2006
Posts
10
I just got my first trailer.  2000 Dutchmen Lite 22 foot.  UVW (dry-weight) 4065 lbs. 

I am towing with a 2004 Chevy Express full-size 1/2 ton van, regular (short) wheelbase, passenger model, AWD, 5.3 liter, 4-speed auto tranny, 3.73 rear end.  Rated to 6200 for towing.  I live in Washington state, so I took 20% off 6200, giving me 4960.  So that leaves 900 lbs. for water, propane, and camping gea, which should be enough.

I drove it home unloaded last night.  On totally flat hiway, no wind, it had a hard time keeping speed at 62-65 mph without downshifting.  I had it in Cruise, Tow mode.  It would downshift, get up to speed, then shift back into 4th, and repeat this a couple minutes later.  I tried 60 mph, it was better, but not great.  Without Cruise, still needed to downshift.

I thought I was playing it safe with 4065 pounds.  I don't want to kill my van.  Do I need to cruise at 55?  I hope not.

Shakedown trip planned for tommorrow night, close-by.

Any advice would be appreciated.

Thanks,
Doug
 

Gary RV_Wizard

Site Team
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Feb 2, 2005
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74,421
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At our Silver Springs FL home
You did well to allow the 20% "headroom", but be aware that you may not actually have the full 6200 lbs available to begin with. The 6200 is a best case max and it wil be reduced by the installation of some factory options. You also have to reduce it by the load carried in the van, anything other than the driver and fuel. (i.e. passengers and any gear) And is the driver weighs more than 154 lbs, subtract the extra there too.

You might want to weigh your van with you in it and full load of fuel. Compare that to the "unladen weight" or "curb weight" listed on the specs for your van. You will likley find it is substantially larger than the brochure says. Since the max tow rating is based on the brochure weights, any actual weight over the brochure unladen/curb weight must be subtratced from the tow capacity.  You should also weigh the trailer, since it is common for them to weigh more than the trailer brochure claims. Sometimes quite a bit more, since factory options on the trailer usually aren't counted in the brochure weights.

The sort of shifting you experienced is called "seeking" and indicates  that the transmision is riding on the borderline between two gears.  No sooner does it upshift then it encounters a small change in load (perhaps an imperceptible grade) and it down shifts again.  Using cruise control exacerbates the condition because the cruise won't let the vehicle slow for even a moment, so I would turn it off. That might help. A lower or higher speed will also get away from that shift point and might help stay in one gear.  Worst case is you might have to drive with the overdrive off (shifted to next lower gear). Since you are hovering near that next lower gear anyway, there won't be any real difference in fuel economy.

Your problem is probably caused as much by wind pressure as by weight. Any Rv has a bluff front end and that pushes a lot of air out of the way. Your modest size engine and 3.73 axle are more oriented toward fuel economy than tow power. A larger engine might actualy get better fuel mileage when towing (but not when the trailer is left at home).

 

ahiburger

Member
Joined
Apr 3, 2006
Posts
10
Gary,

I will weigh everything when I get a chance. 

We camped this weekend.  We loaded up with water, propone, food, wife, two little kids etc. and it towed fairly well, not as bad as I thought it would.  I will have to keep the speed down to about 60 on the flats to keep it from seeking, and kick out of cruise control for any grades.

This is one factor I did not consider when choosing a trailer over a motor-home.

Thanks!
Doug

 

Carl L

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Joined
Mar 14, 2005
Posts
7,239
Location
west Los Angeles
You probably are not going to kill your van.  However, you may have to lock out OD when you tow.  I am in the same position with an old, 1995, Ford Bronco pulling a 4650 lb TT -- for the past 89,000 miles.  Tho I can cruise in OD on the flats, it does not take much of a grade to slow me to direct and a bit more will find me in 2nd.  Get used to it.  I once went from the AZ state line to Kayenta in the Navajo Rez in 2nd because of a really stiff headwind.  Even without a headwind, a van with its bricklike cross section is not going to slide thru the air without resistance and air resistance increases asymptotically after 50mph.    Furthermore, you lose 3% of your rated HP for every 1000 feet of altitude you are running at.  At 7000 feet on the Colorado Plateau, let me tell you my old Bronc is wheezing.

However, before you get jealous of motorhomers, keep an eyeball out for the Class C's on grades and at altitude.  Count up how many pass you, and how many are right with you in the slow lane.  I believe you will be reassured.  Ignore the Class A's:  a quarter million plus can buy a lot of big deisel engine to ram them thru the air and up the grades.

 

82corvette

Well-known member
Joined
Mar 19, 2006
Posts
287
Location
The Cornhusker State
One thing you should consider the GM 5.3 & 6.0 engines develope horsepower & torque at higher rpms than the older engines.  Also when the computer sees that the transmission is warming up, it downshifts to bring the rpms up to spin the front pump faster to increase fluid flow.  I find that unless I am cruising on a fairly flat road the cruise control pulls the throttle open farther to keep the speed constant. Most of the time I don't use the cruise control.  Alan
 
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