My 1994 F-250 is rated at 8600 lbs on the door sticker. A lot of parts for the truck are listed as being for either under 8500 lbs or for over 8500 lbs. I've found both on this truck. The serpentine belt turned out to the under 8500 version. Most other parts have been for the over 8500 lbs truck. Sometimes I'm just not sure which to use.

I have seen '96 or '97s with HD after the F-250 emblem. I always assumed those were similar to the earlier over 8500 lbs versions.

What determines this over/under rating?

 

The springs and rear axle are the main part of the equation. Light Duty F250s got a semi-floating Sterling 10.25" rear axle. Many refer to it as a heavy 1/2 ton truck. The heavy duty F250 for the full floating rear axle like the F250.

Semi-Floating Sterling 10.25 rear axle



Full floating Sterling 10.25 rear axle

 

To figure out what parts you need, just figure out what truck you have. If your GVWR is over 8,400 lbs, use the "over 8,400 lb" parts. if under, use under. And rla2005 is right, the semi-float or full-float rear axle is generally the best "tell"

As to why the difference, back in the '70s, when the EPA started requiring cars to meet tighter emissions standards, they decided to include half ton trucks as well. All half tons made at that time had GVWRs below something like 6,200 lbs so that was the break point the EPA used (I might not have the exact number correct).

Of course the auto makers saw a way around that and right away they came out with "heavy half tons". Ford called theirs the F-150 (previous Ford half tons were F-100s).

So in the early '80s the EPA decided to see that move and raise it,. Since all 3/4 ton trucks were around 7,600 lbs GVWR the EPA included all vehicles up to 8,400 lb GVWR. So of course the automakers all came out with HD versions on their 3/4 ton trucks.

So the "light duty" 3/4 tons are really just standard 3/4 tons. Heavy half is (incorrectly) applied to them at times, but it really means what has now become a normal half ton. And Ford muddied the waters even more in '97 when they first had a "regular" F-250 that looked like the (then) new F-150 and an F-250HD that still had the old body style. And then they muddied it a little differently a couple years later when they renamed the standard 3/4 ton the "F-150 7,700"

 

Thanks for the info.

I have a full floating rear axle with 4:10 gears. I tried looking up the spring code to see if that gave anymore info but that code was not in the book. I'll assume this to be a HD based on what I know now.

Like I mentioned earlier, it was a little confusing when the belt that fit was the under 8500 lbs version. That was the first thing I changed. Then when I went to get some brake parts the over 8500 lbs parts matched up. I just have to double check everything.

I love the truck either way. It's kind of like riding in a tank. It just goes through anything.

 

Unfortunately it doesn't seem like Ford was always very rigorous about using only certain parts on any particular model. At times it appears that they used whatever they had laying around. Combine that with 18 - 29 years of previous owners keeping the truck going and it can be a bit of a pot-luck!

 

what determines the under/over is the GVWR.your truck is the HD version.
a serpentine belt is a belt regardless of the GVWR.that one there sounds like a auto store part number error more than anything.when buying brakes and parts always use the over 8500 lb to receive the correct part.if you get something wrong,it's likely the stores fault.not whether or not you have the HD or LD f250 or mixed parts.