After doing a lot of searching and reading numerous official Ford sites I cannot understand what makes a f-150 a 7700.
is it just f-250 LD or the f150 with a HD tow pkg?
Does anyone have a relatively simple explanation?

 

F150 with heavier axles.......... you would have 7 studs per wheel , where the F150 had 5 and the F250 had 8.

 

if there's a f150 7700 with heavier axles then what do they call a f-250 light duty? The tow capacities seem minimal IMO.
I think I'm going to settle for a complicated engineering wonder brought to us by Ford.

 

The heavy duty tow package is a different option independent of whether or not the truck has 7 lugs.

In 1997 when this body style was new, only the F150 was upgraded and the 1997 F250 with 8 lugs retained the older body style until the release of the extremely successful Super Duty which went on sale in early calendar year 1998 as a 1999 model.

Ford made a weird decision in 1997 to offer the then new F150 body style with a "Heavy Duty Payload Upgrade Pack" that included 7 lug wheels, heavier duty 10.25" rear, stronger 4R100 transmission, bigger brakes, and beefier suspension. And the weird part is that they called it an "F250 Light Duty" in those first couple of years that it was available. Having 2 totally different trucks with completely different body styles both called an F250 on sale at the same time has caused much confusion to people that don't bother to do any research on the matter. It is really pretty simple.

In 1999-2000 Ford dropped the "F250 Light Duty" designation and the 7 lug became the "F150 7700", so named because the GVWR was 7700 pounds. This is a significant payload increase over F150s with 5 lugs. The 7 lug package was available through the next couple of generations of F150 bodied trucks as well. In later generation F150s the GVWR for the 7 lug trucks was more than 7700, but they were simply designated "F150".

It is what it is.

Once people get past
"Why did they...?"
and
"Well they should have..."
And learn about what actually IS, they can easily figure out which truck is which.

 

What's confusing is the regular f-150 the f150 7700 and the f-250 LD. I bought a late 99' f150 xlt 5.4 4r70 3:73 LS,
hd tow, 4 wheel discs 9.75 RP, not knowing what I bought I started researching and that's when
​I got got all confused.
Through the original owners manual and Vin I think I figured out the payload which was my original goal.
Thank you Sam I am, for giving a little more insite on the 99'+ SD, I was not aware, so I looked it up and learned something new..
edit; some of the options on my new to me truck where just that " options " that's what triggered my search.