I have seen different things in different places regarding this. What are the difference between an F250 and an F350 Single rear wheel truck? Are the front axles the same? Rear axles? Different rear springs?
* Up til about 2004, 4 wheel drive F250s got D50s while F350s got the D60.
* F250s typically get the upper aux spring as part of a package, while F350s usually have them no matter what.
* After 2011, F250s have one fewer leaf and vacuum boosted brakes while F350s get hydroboost (diesels only).
* V10s with factory 4.30 gearing get the Dana Super 60 7000# GAWR front axle.
* Up until at least 2008, F250 2wd - no spacer, F250 4wd - 2" spacer, F350 2wd - 2" spacer, F350 4wd - 4" spacer
It's easier to list what are identical (or substantively so) inside a MY:
- Rear Axle
- Rear main leaf pack (through 2010)
- Front springs (rating is dependent on package and engine mainly, but any ratings of spring should physically fit in a truck the relevant major year ranges of 99-04, 05-07, 08-10, 11+)
- Wheels and tires
- Sheet metal and trim
- Availability of certain options are package and trim-based and not badge-based, (but might be standard on 350s and optional on 250s) - cab lights, alternator upgrade, snowplow package, block heaters (or cord, as relevant), access controls, powered accessories, interior upgrades, etc
Yes, a 2003 F250 could possibly have a D50 rather than a D60. I don't know exactly at what point the switch was made, it seems to me that F250s started getting the D60 in late '03, but they might have started as early as the 2001-2 MY. Excursions apparently all got the D50, I don't know if that continued through 04-05 when the platform ended. Other than that, they're substantively identical except for what Texas Rebel specifically mentioned.
Other than a GAWR of 5000# instead of 6000# and a smaller ring gear/pinion, there's nothing "bad" about the axle in a stock application. Nothing I would not buy a truck over at least.