It's all good. That is why I opted not to spend the $600 for the extra "100 units of Ford toughness".

 

Now thats classic... even though I am a 350 kinda guy lol!
I was even over the 350's higher rating saturday, although when your sitting on the axle stops I suppose both are rated the same - no suspension left in the picture lol.



But I know there isnt any real difference anyway

 

I asked that question awhile back and all I can see difference between the F-250 and F-350 is the additional leaf sping on the rear. That gives it more carring weight. Other than that I know no other difference.

Jump in if you know more.

 

The srw F350 has a slightly larger diameter rear axle with more splines than the F250. they both use the same housing though.

 

That "additional leaf" is the upper auxiliary spring, which is standard on F350s, and optional on F250s based on selection of certain packages, like the camper, snow plow, or heavy service packages. I can vouch for this, because it's what I have.

I'm still offering a standing bet of $20 to anyone on FTE with an F350 SRW who is willing to pull one of their shafts to verify this with pictures and a caliper. This statement is commonly thought to come from a misprint in the 2005(?) book, listing the D80 axle shafts from the DRW trucks, but, again, no one has ever posted a picture to prove it in response to my offer. I promise, I'll send a fresh $20 via USPS to anyone who can put up pictures of a shaft being pulled from a 350 SRW to prove this; I'll be happy to get proven wrong, I just want a picture that I can save, compare to mine, and use as proof one way or the other.

You're right about the housing, the Ford/Sterling 10.25/10.5" axle housing has remained largely unchanged for a very long time.

EDIT: I don't say that the axle shaft argument is true one way or the other anymore, because I can't prove it because I don't have any access to a 350 SRW at all. Personally, I don't know why Ford would go through the trouble of having different parts (and different part numbers?) for the shafts, seals, bearings, and differential over 2 splines and .3 inches, for a cost of >$0 and performance gains of nothing. Since ~2003 (when the D50 phase-out was happening/finishing) the driveline has been basically identical across SRW trucks, this just seems like way to nuanced of a detail to be true. But..... 4wd V10s with factory 4.30 gearing were built with Dana Super 60 front axles, so maybe it's a detail like a gearing switch down deeper to 4.30 necessitates different rear end internals. Somewhere around 4.30s and 4.56s is where some carriers get changed to account for deeper cut gears, maybe the factory 4.30 rear end is different, so only certain 350s (and maybe some 250s?) have different shafts. But still, $20 bet.

 

Easy just go into Ford and get the part numbers for a 250 and a 350 axle. I for one don't feel like pulling it apart. The info was on the build sheets and books for many years. It wasn't the axle from the drw trucks. It is lighter.

 

Funny you mention that, last time I ran a 350 VIN through the parts counter, almost everything came back the same Only spacers and ubolts were different, which is why I took that particular VIN in with me instead of my own.

It's just funny to me how people keep putting up the info calling it the gospel truth, but no one is willing to actually back it up.


Just like the salesman told me how the brake rotors on 350 duallies are so much bigger, but somehow fit into 17" wheels, just like the 250s

 

I will have to agree with Bryan.
What i have found, not in every case or every model and speaking for 99 to present, First, second and third generation.
The 2011 trucks have the "locking" option only available on the Sterling 10.5.

 

Dave, that's the exact thing I was looking through my stuff for and couldn't find. I'm not saying that some trucks don't have different shaft sizes in the same housing, I just see it being driven by a lot more than just 250 vs 350. In the grand scheme of things, it doesn't really matter that much to a payload argument, because the internals have less to do with load bearing ability than the housing does, and more to do with power transfer; the GCWR doesn't vary by badge, just engine and gearing.

 

Bryan here's a good article from Four Wheeler Magazine from a super duty rear axle rebuild also. It, in my mind anyway, confirms the same axle shafts for both trucks.

Ford Sterling 10.5" Axle Rebuild - Four Wheeler Magazine

There's also some info in Wikipedia about it......looks like Dave beat me to it but here it is:

Ford Super Duty - Wikipedia, the free encyclopedia

 

Hasnt there been multiple folks who have added lockers and such to srw 350's and verified the same 35-spline axles? I thought this myth was busted a long time ago as a typo in the build sheet.

 

This is a 2009 specification from the Fleet Ford site.. It says there is a difference... But this might be the misprint that you where speaking of...