This is what I have: 2001 GMC Sierra 4x4 SLE ext cab. 

I need to know how much of trailer I can safely tow.  I know that I have to take into consideration payload ( which I undertand to be ANY contents added to a vehicle or trailer).  Also how do I know how much any particular trailer weighs empty?  Is that info available in the same place as the GVWR info is located?  HELP....my head is spinning with all this neccessay information

Sage, Welcome,  Yes it's confusing as to what trucks can tow. I can see why it makes your head spin.

We need to know what you have,  GM made half ton, 3/4 ton and 1 ton trucks in 2001 that all said Sierra SLE on the side. They came in Long Bed, Short Bed, Gas vs Diesel,  Manual vs Automatic, and probably with a couple of rear end gear ratio  choices. The informaton you have given us in not enough info to give you any advice.

I suggest you look at the sticker on the inside of your trucks drivers door as to what your truck is rated for. That sticker will usually give you the total GCVW that your truck is rated for.  Next you will need to run it across a certified scale to see how much your truck actually weighs. The sticker will get you in the ball park of what the truck is rated for,

There really are several numbers you need to know.

1st. GCVW  This is how much total Combined weight the truck is rated for. This is a number for Both the truck and trailer and everything you pile inside.

2nd. Towing weight   This is how much your truck is rated to pull. They usually give two numbers, Conventional and 5th wheel ratings.  Meaning bumper hitch or gooseneck/5th wheel hitch. This number usually reflects the GCVW minus the trucks weight to equal the what the truck wil tow.

3rd. Maximum Payoad.  This is how much weight can actually be placed on your trucks axles and does not include the weight that rest on the trailers axles. This is often calculated by taking the trucks GVWR and subtracting the trucks actual weight.

Each of these weights will be different depending on the model of truck you have, it's engine and transmission.  Most of the spec sheets will say that a 3/4 ton is rated at a certain payload,  Then you need to look at what your truck weighs empty. For example a Ford 250  can have a 9000, 9200, 9400, 9600 9800 and 10,000 GVWR  A regular cab, gas engine, short bed, 4x2 truck might weigh 6100 lbs - the 9000 GVWR = a payload of 2900.  Where as a Crew Cab Diesel, Long bed, 4x4 truck will have 10,000lb GVWR rating  but since the truck weighs 8400 lbs can only haul 1600 lbs of payload.

We as internet friends will only be able to give you ball park answers.

As far as trailers, They also have a sticker showing what they are rated to weigh. These show what the trailers rated maximum loaded weight can be. Very few trailers actually show the empty weight.  But a call to the manufactures can usually get you a ball park number of what it weighed empty. The manufactures are shipping their trailers, so they get used to what they are paying for to the shippers.

Even with the knowledge of what the trailer weighs, you will need to find out how much of that weight sits on the trailer axles and how much rest on the truck. And the only way you will find those numbers is to load the trailer up and run across a scale.

Let us know the following:

Is your truck a 1500, 2500 or a 3500.  What engine does it have, is it a Long bed or short bed.  You already told us it's a extended cab. From that info somebody can look up the GMC Specs and give you an idea.

Its a 1500 with a 4.6L engine ( whatever that means )

GVWR 6400 ( there is not a number that indicates the GCWR )

On the bumper it says MAX tongue = 500 / MAX trailer is = 5000

On the hitch it says MAX tongue is = 600/ MAX trailer is = 5000

thanks so much for your help.  Seems like I need an engineering degree to figure this stuff out

First you need to know what engine, transmission, and rear end gear ratio you have. After you find that you can look up the trucks tow rating here.....

 http://www.trailerlife.com/images/downloads/01towingguide.pdf

So far as the trailer's weight, take it to a truck stop scale, then you can weigh the truck and trailer together and get the Gross Combined Weight.

If it's a 1500 GMC pickup, then it's a 4.3 V6 or a 4.8 or 5.3 V8.... There was no 4.6 V8 in a GMC pickup. 4.6 V8 is a Cadillac engine. Take a look again.

These stamped trailer ratings are for the bumper/hitch ONLY.   Like a Chain, the weakest link determines the strength of the complete system.

The max trailer weight your TRUCK can safely tow is likely lower.

Looking at the post that Retento posted above,

Your truck is rated to tow 7800lbs if it has the 4.10 rear end and 6800 if it has the 3.73 rear end.( I  bet you have the 3.73)  that's assuming you have the 4.8L V-8. That should pull a two or three horse bumper pull. But I don't think you will find many goosnecks that will fit into the weight range.

With your bumper hitch rated at 5000lbs.  Two horses = 2000-2500 lbs.  Your trailer will need to weigh 3000lbs or less.

Of course yesterday I saw a Ford Ranger with a 4 horse steel stock trailer hooked up to it.  I don't know how many horses he was loading in it. But I'm sure he was over his rating.

No it doesn't.  The ability of the truck to provide safe stopping distances is specifically addressed in said truck's GVWR.  Don't overload your truck or trailer axles and it will stop fine.

Pardon me?

Ah, perhaps I was unclear as to my more generic meaning, of what I thought was encouragement....

(Just because you can tow it doesn't mean you should, and certainly doesn't guarantee you can stop it.) We have all seen folks whose enthusiasm overloaded their wisdom, so to speak...

By Sage making inquiries to learn, means that by gathering and utilizing accurate information, will address the issues of towing and stopping.  That is a good thing, is what I meant.  Both issues are a concern to the horse towing owner, as they should be.

The ability of a truck to stop safely while towing a trailer is dependant on many factors. "The ability of the truck to provide safe stopping distances is specifically addressed in said truck's GVWR." This statement is simplistic and not complete.

The same weight trailer, will change the towing vehicle's balance and handling characteristics, depending on if it is using a bumper pull or goose hitch. The goose hitch results in a more balanced load, and provides a higher degree of security, especially when braking while turning.

The tires being used, with their various thread depths and designs, will effect braking distances. Environmental elements will also cause changes; ice, rain and snow can all greatly change the stopping distances. The tires' construction, radial or biased ply, will effect braking distances and towing characteristics. Varying the tire pressures, will change the braking abilities of both the towing and towed vehicles.

The mechanical condition of the trailer's brakes will greatly change its ability to stop. A rusted rotor will lessen the electromagnet's ability to apply the brakes. Worn shoes or a rusted drum will reduce the braking ability. A dirty or corroded electrical connection to the towing vehicle, can degrade the braking system's characteristics. The controller being used, will change the braking time and application strength. If it is improperly adjusted or not working correctly, braking distances will suffer.

The driver's knowledge and experience, will effect the outcome and success of a panic stop while braking in a turn. The same conditions could result in a close call or a bad mess, depending on the driver's abilities.

None of these circumstances are specifically dependent on the vehicle's GVWR for a successful tow. I suppose someone could pull a six horse trailer with a Geo Metro. Being able to do so, doesn't mean it can be done safely. Real world conditions are more determining than statistics.

BOL  Gard

I'm sure she appreciates your clarification.

That statement was complete, in the context of my post.  However by quoting one sentence out of my post, which you tend to do, I can see your confusion.  I will agree my whole statement was simplistic, and was intended to be.  Generally when someone has to ask on a forum about their tow rating, simplistic is what they're looking for.

If I go even simpler with the fact; "truck brakes stop the truck, trailer brakes stop the trailer" then technically your reply is not even related to my statement.  The majority of your examples above pertain to the trailer's ability to stop itself, and have nothing to do with the truck.......

It's always so entertaining to read the "how much can I tow?" threads on this site!...

So many options... So many opinions.... so many variables... and so much attitude!

Gather as much research as you can and try to make an educated purchase.  Then go out and practice driving, but without your horses.  If you have made a mistake in your choices you certainly don't want them to suffer for it.