Bill, the "PSD" part is Power Stroke Diesel so in 2003 it's either the 7.3 or the 6.0.
I'm not sure about the 2003 but the 2005 F250 uses the same axle, brakes, etc. as the F350. The only difference is the F350 comes with an overload leaf on the springs and a rear stabilizer bar. And maybe a higher spacer to make it sit higher. If yours has the Camper Package meant for the slidein camper then it has the same overload and stabilizer bar as the F350. I added air bags to accommodate for mine not having the overload spring so feel despite the numbers, realistically my F250 can handle the same payload as the F350 in same configuration. Some here will argue but I have yet to find anything to convince me otherwise. I'm towing about the same weight, maybe a bit more than you will be and the F250 does an outstanding job. It now has just under 65k miles.
If you want to check yours, the overload leaf sits on top of the spring pack and looks like it is upside down, curving upwards on the ends, like a smile. The 3650 has one of the lighter pinweights, which is to your advantage. Keep in mind you will technically be over the rated GVWR/payload so the airbags may be necessary to keep things level.
On edit -- disregard my suggestion about airbags. I see yours already has them. Enjoy the 3650RK. It's a beautiful model.
See another Montana or Mountaineer on the road? Flash lights twice, it might be one of us!
Steve Reigle (pronounced Regal)
Fulltiming since 3/21/03
'07 3400RL
'05 Ford F250 SD Lariat CC SB 6.0L PSD/TS FX4 4x4
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