I have a 97 f150xlt super cab with 4.6 engine and 3.08 axle ratio. I looked at the specs at the right of the page and it states that the max trailer weight for my truck is 2000 lbs. But it also lists the gross combined weight rating (gcwr) as 10,000 lbs.

Now it was my understanding that gcwr - vehicle weight = max weight of trailer. If this is the case, I should be able to pull a trailer of around 5700 lbs since my truck weighs 4300 lbs.

Why does ford limit the trailer weight to 2000 lbs and then state that the gcwr is 10000 lbs? It doesn't make sense. Is it something about the 3.08 gears?

The reason I'm so concerned with this is I'm getting ready to purchase a boat that weighs around 3500 lbs with trailer. I would have thought (just by gut feeling) that a truck of this size and weight would have no problem with this size trailer.

Should I see about changing the rear axle gears or just wait and see how it does with this weight before I mess with anything? Does anyone know why ford would rate this truck's trailer towing so low? After all, this is a very heavy truck with a v8 engine? Why would ford make a full size truck that could only haul 2000 lbs?

 

It's the gearing. Good for MPG's, but bad for towing.

 

I posted this same question awhile ago and got no real answers.
The funny thing is I bought a used 2000 F150 s/c 4.6l with a factory tow package (which they recommend if you tow over 4000 lbs) and I found out later it has a 3.08 rear end rated at only 2000 lbs. max. according to the manual (sounds kind of strange!).
Meanwhile the 3.31 rear end is rated at 10,500 GCWR/6,200 max trailer weight. We're rated at 10,000 GCWR/2,000 max trailer weight. I personally think they rate the 3.08 extra low at 2,000 lbs for warranty reasons to cover their butts. As you say it should be rated at 5,700 lbs according to the GCWR.
I tow a boat/trailer that weighs a total of 5,500 lbs with mine and I've had no problems, though I always turn off the overdrive. It's a bit sluggish getting started but once up to speed it tows great. We are planning on a long trip with the boat this summer and I plan on adding a transmission temp gauge so I can keep an eye on things.
I don't think the 3,500 lbs. you're towing should be an issue though if you're going a long distance the temp gauge might also be an option.

 

Wow thanks for the info!!

If you are towing that much, I should be fine. Does your tow package include a transmission cooler? If so, I'll probably just get one of these and call it good.

Thanks again!

 

If this is true, then why did you say this:

The low rear end keeps your engine revs too low to get any power. You adjust by taking the tranny out of overdrive, which forces your engine to rev too high and causing your T/C to unlock, heating up the tranny.

Ford does cover their backsides with the towing limits, but there are also some good reasons for the limits that they give.

Do I think that a 3500 lbs. trailer will kill a 4.6L with a 3.08? No. But it is not a good set up.

 

I don't see your logic. The reason for the overdrive cutoff is so that the transmission doesn't continuously switch from 3rd to 4rth while towing. It's this switching back and fourth that is damaging to the transmission. That's the reason for the switch. You are supposed to turn off overdrive when towing a heavy load.

 

No, you're not. You switch off OD if the tranny is hunting between 3 and 4. The tranny has to hunt because it does not have enough torque at the low rpm's 4th and the 3.08 are giving it, so it downshifts to 3 to get the rpm's up. With a lower rear end, the tranny probably will not have to hunt so much.

Now that's true.

 

It looks to me like the problem is the engine. My dad has 3:07's in his 78 F250 w/ 460/C6 and the rear end puts out enough torque. Truck was originally bought to pull an airstream trailer all over the country. I will add that when towing, the 3:07 is a little sluggish, as compared to a 3:73. Could be that there isn't enough power going to the rear end.
Companies do like to cover their (expletive). But remember, if you get in an accident and it comes out that you were exceeding the tow capacity, guess what...your fault. Not to mention, the truck has to be able to not only tow the trailer, but stop it as well.
Tranny coolers are definitely nice, I recommend an oversized one (for the sake of overkill) A tranny temp guage would be nice too. And of course a brake controller, WDH, and all of those other gizmos.
Now somebody asked why are these trucks only made to tow 2000lbs? Well - they are not designed to tow, its more of an afterthought. Trucks are now considered passenger vehicles, therefore their energies are going to be dedicated towards handling and passenger comfort.

 

His '97 4.6L has 220 HP@4500 rpm, 290 ft-lbs.@3250 rpm

Your '78 460 has 230 HP@4000 rpm, 362ft-lbs.@2600 rpm.

The 460 has a lot more torque and it comes on at a lot lower rpm.

The 460 can take a taller rear end than the 4.6L

 

Yes the tow package does have a tranny cooler. I turn off the overdrive because the the transmission is hunting between 3rd and 4th at highway speed. This keeps the revs up higher but they're not getting to high in my opinion since I'm taking it easy at the posted speed limit. With the OD off shouldn't the T/C stay locked up? It seems to as far as I can tell.
One of the reasons I bought this truck was because it had a tow package. I only found out about the 3.08 rear end from the original window sticker that was in the owners manual. A friend of mine bought a new 2002 with a tow package and it also came with the 3.08 rear end. Why do they do this?
As far as exceeding the tow capacity of the truck: In my opinion I may be exceeding the tow capacity of that rear end but the F150 s/c itself is rated to tow up to 6,600 lbs with a 3.55. Therefore I may be taking a chance with the tranny (thats why I'm getting atemp gauge) but the truck is rated to handle the load. I also make sure that my trailer is well maintaned with proper brakes.

 

No problem. So long as you realize that you are compromising other systems in the truck, I see no problem with that load.

Engine/tranny long term durability is probably bettter with the 3.55.

 

When still had my '97 Ranger, which I bought new, It stated right in the manual: TURN OFF OVERDRIVE WHEN TOWING ANY LOAD.
The overdrive internal are not designed to pull a load. They are strictly for the purpose of lower the rpms at high speed to get us the better gas mileage.
Second. Here is my experience with ANY ratings. They are ALL under-rated to reduce liability. The class 3 receiver hitch on my '77 F150 was rated at 5000lbs max. I tow a 7000lb trencher on a 5500lbs trailer. No problems. When I first bought my '90 F250, I had only the bumper to tow with. I pulled a low-boy car trailer and my Mustang around and I know it was over the 5000lbs rating of the bumper.
Just my 2cents worth.

Stryder

 

I believe the Torque converter will lock in 2nd drive and od.
In my 2002 ranger manual it does NOT mention to avoid OD with a trailer.

Rand

 

The whole reasoning behind turning the O/D off on an automatic is that the tranny tends to "search" between drive and o/d in certain situations. It is this searching in the tranny that heats the fluid and kills them.

With a manual, you won't be "searching", you shift when you want to and nobody with a nickle worth of sense will set there and shift the tranny back and forth just for fun.

Secondly, everyone, tow ratings are not just the amount of weight a vehicle can pull, but the maximum safe amount of weight a vehicle can STOP.

I really wish people would understand that. If the brakes fail on a trailer, and it is overloaded, how are you gonna stop if it is over-loaded.

 

Expanding on jschira's post:

The 78 F250 has a big heavy Dana 60 designed when 3.08:1 gears were almost considered towing gears.
The 97 F150 has a lighter duty Ford 8.8 or 9.75.