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ipso_facto 03-18-2003 10:52 AM

Another towing question
I have an 80's 32' Excella rated at 8300 lbs dry according to the manual. Full, I expect it to weight at just under 10,000 lbs. I will need to tow this unit probably 2,000-3000 miles/year, not that much and not often. Most of it in the mountainous or semi-mountainous region.

I have a '90 F250 HD with 460, 4.10 rear, C-6 tranny and full size bed/super cab, the full towing package. It tows it nicely. Problem is, it doesn't like normal highway driving much and prefers 50-55MPH. At 65, the RPMs hit 3100 and mileage drops to something like 10MPG, empty. Towing, I got 8.5MPG at under 60, although I could get almost 10MPG if I kept the RPMs at 2500.

I need a vehicle which will be used as a daily driver 90-95% of the time and for towing this A/S the rest of the time. I want something that can get me 15-16 MPG at normal highway speeds and not get high RPMs - and still be able to tow without problems. I need an OD but I realize I won't be able to tow in OD.

My options are:

First, Get a smaller truck, with a small block V8, 351W or 350 Chevy. In either a "Heavy Duty" or non-Heavy Duty version. F250HD came with either big/small block motors and I suppose so did Chevy. Regarding the rear end, either 3.37 or 4.10. HD would come with a HD tranny as well.

Ford towing guide rates F250 HD with 351W and 4.10 rear at 8500 lbs as its towing capacity. So I would be exceeding it by 1500 lbs. How dangerous is that? Is that rating an absolute fact or merely a guideline? There was no 3.73 end available in "HD", only 4.10 and 3.55. With 3.55, it is rated at only 6500 lbs. I don't know the numbers for Chevy/Dodge but don't think they are really different.

I would like to hear from someone who tows a 32' unit with a small block V8 with any make. I realize I would want tranny cooler. I would like to know what kind of mileage it gets empty, towing, what RPMs it hits on the highway and what's the rear end. My main concern is, I don't want to overheat and ruin the engine or tranny, ending up penny wise but pound foolish. I don't care about towing performance, I just want to get from point A to point B safely without breaking anything.

Second, Get a Gear Vendor Overdrive. Pretty expensive option at about $3,000 and not sure how much MPG it would actually add. Probably none, because the only thing it does is it would lower RMPs by 22% as they claim. Meaning at 64, it will idle only 2200 or so, resulting in probably 12 MPG.

Third Re-gear the truck to 3.55 rear. According to Ford, I will lose 200 lbs of towing capacity. 460/3.55 are rated at 9,800 lbs of towing versus 10,000 with 4.10 rear. I hear this will lower RPMs by about 15%. So at 65, it will run at 2600 or so. Meaning at 65, get an extra 1 MPG and highway driving will be a better experience. Doesn't really save me any gas per se, just allows to drive faster.

It is very doubtful the 460 can get above 12MPG no matter what you do with it. So options 2-3 would only make highway driving more bearable, RPMs more normal.

I know I have other options too, like getting a diesel or keeping this truck and getting a small car for daily driving. I would get a diesel if I had to tow a lot, I doubt I want a diesel for only 2,000 miles/year. The small car option doesn't work for me either because it is an inconvenience.

Any comments would be greatly appreciated.

59toaster 03-18-2003 10:57 AM

Those power strokes are monsters! 19-21 mpg empty and plenty of power to pull what you got and proably get 14mpg while doing it.

If I were buying new and had the cash that's what I would get.
Now understand that the difference between a F350 and af250 The new ones is springs and Dually.....Go look at it's GVR ;)

rcmenz 03-18-2003 11:21 AM

I did LOTS of research on the internet, then lost out to TLOML ( so now we have a 25 footer, not a 32). If you are trying to save some money, I would take a hard look at the GM 6.5 Turbo diesel. They have a bad reputation, and as a result seem to sell for less. The big problem is the electric throttle. The gizmo mounts to the side of the electric fuel pump and has a bad habit of overheating the pump, causing pre-mature failure of an expensive part. Of course there is now a kit to mount the gizmo elsewhere, solving the problem. The second issue is lack of maximum output compared to Doge or Ford. The GM runs only five pounds of turbo boost, while Navistar and Cummins run 15 pounds. Somebody re-built a GM ( changed the comperession) and ran it at 15 pounds of boost. It then matched the other two for maximum output.

Driving empty most of the time the lower output wouldn't be a problem. Parts should be available for a long time as this is still the standard engine for the AMG Hummer.

Just my 2 cents worth.

davidz71 03-18-2003 12:40 PM

A good diesel would suite your situation just fine. If you didn't want to spend the money on a new Chevy Duramax diesel or the new Ford diesel then I would go with the Ford power stroke diesel. The Chevy 454 and Ford 460 engines are good but you are making a mistake by considering a 3.55 rear end. You should not go lower numerically than a 3.73. I like my Chevy 8.1 with Allison 5 sp. auto and 3.73 which tows my 31' Excella with GVWR of 8500 and towing wt. of somewhere under 7,000 lbs. I would not even consider going to a lower rear end. I need to go weigh her loaded one more time because the last weigh in did not seem right.

ipso_facto 03-18-2003 01:00 PM


I don't want a diesel if I will tow only 2,000 miles/year. If I towed more than 10,000 miles then I understand diesel is the best solution as the ultimate towing vehicle.

What about 3.55 rear that wouldn't work? According to 1990 Ford towing guide, 460/3.55/C-6 is rated for 9,800 lbs. I would be slightly exceeding it by 200-300 lbs. I understand the rear end is crucial in a small-block V8 but 460 will pull anything. But then again, I wouldn't be towing all that much or often.

3.73 was not offered in my F250HD, it was either 4.10 or 3.55. I don't know why. What RPMs could I get with 3.73 at 65?

59toaster 03-18-2003 01:38 PM

Here is a good gear calculator.

Plug in what you know and it will figure it out. DRIVE in a OD tranny is your 1:1 gear. On most V8's the sweet spot in that gear is about 2500RPM at 65mph. That's where most Gas engines usualy are running most effiecent. Also understand that what is printed on the side of that tire in reguards to size is not always what that tire really is.

The poor mans fix would be a set of towing tires (current) and a set of tall tires for the rest of the year as long as you are 2wd. Looks a little redneck but it would lower you engine RPM and probably far cheaper then changing the gears in the Diff. Then when you need the better pulling power you can change back and lower you effective gear ratio in your driveway in about 30 minutes. Problem is it will throw off your speedometer and on FI truck it may throw off the computer if you take this to far. 2 inches in tire hight is a conciderable amount of RPM for a given speed.

As for changing your gear. lowering the RPM does not always equate to better MPG. If the truck is lugging at 2200rpm and you have the throttle 3/4 open to maintain speed, But with the lower gear your turning 2800 RPM but only need 1/2 throttle to maintain that speed your probably using less fuel at 2800 rpm and the engine is actually having to work less because it has less resistance.

RoadKingMoe 03-18-2003 02:00 PM

You already have the smallest truck you should be pulling 10K lbs with!

For a gasser, you have a pretty good truck to pull 10k lbs! The only thing better on a gasser with that load in the mountains would be to have 4.30:1 gearing.

I pull a 34' Limited listed as 8300 lbs dry and 9800 GVWR (you might want to recheck your weights) with a 7.3L Ford PSD, 4-speed auto, 3.73:1 gearing and LT265/75R16 tires (same diameter as LT235/85R16). Without the trailer, this translates to 20 mpg at 2000 rpm at 70 mph in OD.

Out of OD this becomes 2850 rpm at 70 down to just over 2000 at 50 mph... which would translate to 3150 rpm at 70 mph with 4.10 gearing. I sure wouldn't want just a big-block gas motor with 3.73:1 gearing... that ratio puts the rpms down in a diesel's power band, but a gasser needs to run 3,000-4,500 to be in its powerband, and pretty close to 3,000 rpm to even be near it.

A HD or Superduty truck weighs a lot more than a 1/2 ton... but that's what you need to pull a heavy trailer. A small-block in one of these heavier trucks can barely pull the truck up a mountain, much less have a heavy load behind it.

As I said, you have the right truck for pulling your trailer. If you want a truck that'll do both the towing AND get good mileage on the highway at 70 mph, then a newer truck with OD tranny and a diesel engine is the answer. But you'll never even come close to any fuel savings breaking even with the higher price for a diesel engine (about $2500 on a used '96 truck, for example) and the more expensive oil changes.

If it were me, I'd spend a lot less on an older econo-car and commute with that.

RoadKingMoe 03-18-2003 02:07 PM

As 59toaster mentioned, lower rpms from higher gearing (lower numerically) doesn't necessarily mean better gas mileage... you're losing torque multiplication, so you have to stick your foot in the throttle further to make up for that loss.

You may also find that the engine detonates with the higher gearing and have to use higher octane fuel.

ipso_facto 03-18-2003 02:30 PM


Your arguments are awfully persuasive.
I probably couldn't get a better towing vehicle than this one.
Of course something better would be a F250 HD diesel and I don't know if I am ready for that yet. I don't know what problems I could run into when running a diesel as a daily driver.

RoadKingMoe 03-18-2003 04:00 PM

In preparation for full-timin' we've divested ourselves of the Integra and the Ranger, and are down to just the F250. I commute with it 9 miles one-way on 25-40mph streets. In the summer (when diesel fuel is cheaper), I get about 14 mpg on these streets, and in winter, when I let the engine warm up, and when the fuel has additives (and can cost more than premium gas due to competing with home heating oil), it goes down to 12-13 mpg. As I mentioned, highway-only mileage is right at 20 mpg and mixed street/highway mileage comes in at about 17 mpg.

Commuting, I use about 8 gallons/week and with the 38 gallon tank of the longbed, fill up about once a month. Ford came up with a new filler for late-'01 on, which allows you to use the big high-speed nozzles at full flow.

I generally try to fill at truck stops or the local station the city uses for their trucks to get fresh fuel. Diesel quality varies, and if it sits a long time in a tank it can get bacteria and fungus growing in it. I carry a bottle of additive and a bottle of biocide if I have to fill at a station with unknown quality.

Oil changes are 15 quarts, so that's 4 gallons of Shell Rotella T and a huge Motorcraft filter for $35 at Wal-Mart and I pay the car wash quicklube $15 to change it and top off the other fluids. Recommended interval is 5,000 miles normal duty.

I DO plug the block heater in when it's below about 25F degrees and it sure starts easier and runs better. That uses a lot of electricity though, so if I were staying further north, I'd get a heavy-duty timer to let it run 4 hours before I needed to leave.

You get used to waiting for the "Wait To Start" light to go out, and when the truck's in the lot at work and it's below freezing, I wait a full two minutes until the glow plugs go out (the cab light gets brighter and you hear the relay click). The glow plugs actually stay on longer than the WTS light, depending on oil temperature.

That's about it for the difference of commuting with a diesel. I LIKE it!

A supercab/longbed or crewcab/shortbed is a bit too long to be convenient for parking, but I just go out to the edge of the parking lot and back in. But you already know this. The clearance lights on my cab are about 1-1.5" below my 7' high garage door, and my garage is 27' deep, so the truck fits with no problem.

Hope this gives you a little diesel perspective. I think it's the right way to go if you have to tow and commute with the same vehicle. Besides... it's really nice to be towing 10K up a hill at a relaxed rpm just a bit over 2,000 in Drive with the torque converter locked and not generating heat in the transmission...
rather than near 4,000 rpm in 2nd to get the same torque to the ground, and have to worry about transmission temperature.

rtaylor537 03-18-2003 04:03 PM

towing information
My wife and I pulled our 2001 Excella 30ft 7000 miles last summer from Michigan to the West Coast and back. We pulled it through the mountains of Wyoming, Utah, Nevada, California, Idaho and Montana. We were on grades that prohibited semis exceeding 53 ft from king pin to rear axle.
Our tow vehicle is a 98 F150, 5.4L with a 3.55 rear axle. The hitch is a Reese anti sway and weight distributing. Our gas mileage was between 10 and 12 mpg at 55 to 60 mph. We sometimes drove into strong headwinds, were often passed by semis (we passed only 7 vehicles during the entire trip) and after some adjustments to the hitch, never experienced the white knuckle syndrome often used to sell more expensive hitches.
We were passed by fifth wheelers and other tow behinds who seemed to be in a great hurry but I believe our patience and our attention to safe travel was far more important in making the trip enjoyable.
We plan to make several trips this spring to the south east coast of the Carolinas through mountains once again. I do not expect to have any difficulty. If we do, I'll let you know when we return.

femuse 03-18-2003 04:07 PM


I have an 80's 32' Excella rated at 8300 lbs dry according to the manual
I bet you got this wrong and may want to double check that. It is 8300 lbs GVWR. A 1988 is 6300 dry, our 1990 is 8300 GVWR.

Silvertwinkie 03-18-2003 04:38 PM

To be able to pull 8300lbs..... WOW!

That would be like pulling 2 of my cars NET, not gross. :)

And I thought I had it bad with my Bambi and the fuel mileage I get pulling it! :)


ipso_facto 03-18-2003 08:38 PM


I will seriously consider a diesel. I don't have a pressing need at the moment but I will some research and see if it can work for me.


Thanks for the story. But I will be towing loaded. I won't be towing just 6500 lbs but more like the full GVWR.


Of course, upon rechecking, it is 6500 lbs dry. My apologies for confusion. According to the manual, it is 6500 dry and 8300 GVWR. That makes it somewhat lighter. The manual also says that the hitch is 800 lbs, so what's the total weight the truck will have to deal with? Dry weight + all liquids including LP + my stuff (at least 1500 lbs)

davidz71 03-18-2003 08:54 PM

ipso facto,
I think all the comments are worth taking. I pulled my 1977 Excella 500 31' from AZ. to TN. after buying her on ebay. I did it with my then '92 Chevy Z71 4X4 with 5.7 litre (350), 5 speed manual and 3.42 rear end ratio truck. It had been outfitted with a Jacobs Ultrateam high energy ignition that gave me a little more low end torque from stock. She was a great truck but was not the truck for the job with LT265-75-16 tires and that 3.42 rear end. On a straightaway she was just fine cruising at 65 in 5th gear. The slightest hill and I had to downshift to 4th sometimes 3rd. When I hit some of the steep hills in N.M. I had to drop all the way down into 2nd gear to make it to the top and I might have been going 35 mph. Not good. Every semi truck that passed me made me swerve all over and I am using the same Reese equalizer today that I was using then, except for a change in the hitch bar which dropped the ball down several more inches. My '01 Chevy 2500hd 4X4 extended cab doesn't break a sweat with the 8.1 litre, Allison 5 speed auto trans and 3.73 rear end. The truck is wearing a set of Firestone, yikes, Steeltex LT245-75-16 tires which are shorter than the 265's that were on my Z71. I chose this truck over an identical truck with 4.10 and now I wish I had purchased the 4.10 rear and gone with taller tires to fill up the wheel well. I think the 265's would have brought the rear end ratio down to 3.90 and I would have had even more pulling power for hills.

My suggestions on rear end are based on a half-ton truck that was not suited to the job because of rear end ratio and the happiness I have found with the 2500hd with big block engine. I guess I could have bought a 2500hd with 6 litre engine, 4.10 rear end which this engine loves and picked a 25' or shorter Airstream but that is another story. The 460 Ford engine is a good engine that shouldn't be hampered with 3.55 gears. What happened to the 3.90 rear end they offered at one time. That would be ideal.

ipso_facto 03-18-2003 09:21 PM


Thanks for the educational story. You went from a base 1/2 Chevy to a full 1 ton (which is what 2500 HD is I believe). One difference is, I am dealing with an 80's A/S which is heavier than a 70's A/S.

j54mark 03-18-2003 10:05 PM

First, I have a 6.5 turbo diesel, and while I agree that they are nowhere near as bad as often painted, and I also agree that they can often be had at a substantial discount, I don't agree that it would be that great a choice for a 32' Airstream that is going to push gross weight. They just don't have the horsepower, or at least not what I would want. Granted, mine has a 3.73, but I tow a lightly loaded 25' Soverein, and it is enough of a load for me. But there are plenty of people doing it, so I could be wrong.

Second, as others have noted, it would be hard to find a better truck for towing than what you have. Any diesel truck you would want to have would take many, many years to achieve a payback in gas milage. Financially, does it make more sense to write just a $150 check every month to Chevron, or is it better to write a $100 check to Chevron AND a $500 check to GMAC finance?

If you want to throw money at the problem, I'd suggest a Gear Vendors unit. It will give you a true overdrive, and also let you split gears for easier towing. About $3,000, installed. It should get you MAYBE another mpg towing, but ought to let you get about 15 mpg highway when not towing.


ipso_facto 03-19-2003 10:48 AM


If you want to throw money at the problem, I'd suggest a Gear Vendors unit. It will give you a true overdrive, and also let you split gears for easier towing. About $3,000, installed. It should get you MAYBE another mpg towing, but ought to let you get about 15 mpg highway when not towing.

I've come to realize that this is indeed the way to go and everything else is either inadequate in some way or a patch. 15 MPG empty on the highway would be really outstanding for the big 460 and it would still be adequate for pulling with
the 4.10 gear.

Chas 03-19-2003 07:34 PM


My 95 F-250 Powerstroke has 3:55 gears in it. Maybe a bit tall but my former Argosy and my current Overlander aren't as heavy as the 80's models like yours, they got pretty bloated during those years. Gets around 18 mpg on the highway and close to 13 towing. I have some relatively tall Michelins on it presently and even though it pulls great I would like to go a little shorter to get my revs up when cruising. I like to keep the rpm's up above 2000 and to do that now I have to be running around 75 mph. I almost always drive around town with the OD button off.


davidz71 03-19-2003 10:00 PM

I had to go back and read your original post again. Somehow I missed that you already owned an F250 with 460 but there it was was plain as day. You said you don't want a diesel. OK, strike diesel. You can forget the small block 351 because it will not be up to the task on mountainous areas you claim you will travel. I guess that leaves Gear Vendor whether you like it or not because that 460 will be sucking wind with a 3.55 rear. I gave you my experiences because I thought my half-ton was pretty stout. Oh, there is one more solution- get a small block and a smaller Airstream! Let us know how the Gear Vendor works out.

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