Axle swap instead of just springs?? Bad idea?
 

I've been reading as many of the posts on upgrading the springs on my '01 Excursion (4x4, 7.3L) as I can. I was planning on getting it done this spring.

Now I have a dilemma - unless you guys tell me I shouldn't even consider it - haha. I have a chance to get front and rear axles off of a '07 F550 for a very reasonable price. Hub to hub - disc brakes, springs, shocks, everything. Is there any reason that I couldn't - or shouldn't - replace the whole shebang with 550 axles? This obviously wasn't my original plan, but it will save me from having to replace gears (550 has 4.88s) and it's definitely heavy duty! Is it overkill?

I searched the forums and coudln't find anything on this...

Thanks guys. Let me have it, I'm a newbie but I can take the abuse...

I think that those F-550 axles would be too wide for an EX.
And 4.88s are really deep gears for the 7.3, rule of thumb is 4.30s for 37" tires, how big of a tire are you planning?

Ya, kinda figured it wouldn't be a direct swap. I wouldn't be going over 37" tires, probably 35.

It just got me thinking when I saw the ad.

PSD rule of thumb says 4.10 gears for 35" tires. The goal is to keep it around the 3.73-ish effective ratio to retain good towing performance.
The '07 axles would have also been coil spring fronts, so not quite a direct swap even from a F-250/350 SRW truck, doable and a sweet upgrade but not as simple as swapping with a leaf spring front end truck. :-X22

Thanks! Great info.

I do tow a 10K Toyhauler for hunting/camping. I'm mainly looking to replace the worn out originals and end up with a better ride and ~4" of lift. So...I'm figuring X/modB or the equivalent from a local shop. Probably need some front end work too - I'm wearing the inside edge of the front tires. The alignment guys swear they have it right but it's still happening. :-X09

That is usually ball joints and/or hub bearings.

I believe the 450/550 and also maybe cab/chassis 350s have a different length of spring as well, so you would also be having to move spring hangers. It has been a while since I was looking at them, so I could be misremembering....

F550 should be 10 bolt wheels, plus a dually set up that you would have to remove all the stuff for. By the time you go through all that expense you can probably find a 250/350 sonar and be money ahead. Even if this is a good deal. Plus I don't know if you were able to keep the 10 bolt hubs if you'd find rims.