'00 EB 4.6L/2WD Rear Axle swap compatibility

[grantpa]

I'd like to swap out my 3.31 geared rear axle for a 3.73 or 3.90 from a standard suspension Expedition. What years are compatible/interchangeable with my 2000? My thinking is, it's a lot cheaper and simpler to swap the entire axle vs re-gearing. I can't get a gearset purchased and installed for LESS THAN about $750-1000-IN MY AREA. On the other hand, I know I can pick up a complete 3.73 geared axle for about $175-200 and I can install it MYSELF. To give me the best chance at scoring a great condition axle with the gears I want, i'd like to know what other years are straight bolt-on interchangeable WITHOUT having to cut and weld brackets, mounts, etc.? Thanks!

 

[Yager]

97 to 02 should be. Although not sure on u joint sizes as some had the 8.8 and others the 9.75 ring gear. Should be able to swap u joints easy enough if need be. Just find a coil spring rear with the gears u want from those years. Also go with the 9.75. Its much beefier.

 

[grantpa]

Thanks for the response, Yager. That's a great idea going up the 9.75 vs my 8.8.

 

[98eb5.4]

9.75 uses a diff length driveshaft, lotsa other stuff also to sort out,

12mm lugs vs 14

disc or drum setup? pretty sure 9.75 are all disc

3.73 is only on 9.75 that could also be ltd slip,

not aware of 3.90 oem option

3.55 came in 8.8

http://www.car-part.com/

 

[grantpa]

I STILL would like to know WHAT were the Ford engineers thinking in mating a FACTORY-size 32" dia. tire WITH 3.31 gears?!?!?!?!? By all that's Holy, I can't understand why they'd do such a thing and I haven't been able to find a satisFACTORY answer anywhere. I'm thinking I'll stick with the 8.8/3.73 axle that I found at the pick n pull. I believe it's from the same year/make/suspension but with the factory tow pkg. where mine is the standard suspension. Is this correct? Also, does anyone know the part # of the CORRECT kit to add an oil filter relocation kit??? I've tried searching, Jeg's, Summitt, etc. and can only find generic one-size-fits-most kits.

 

[Yager]

Mine has a9.75 and 3.55 ls. Suspension is the same as long as it's coil sprung. Driveshaft maybe your only difference. U can get a driveshaft made for $200

 

[Yager]

Grab one off a 97 or 98 expedition or f150. They came factory on those. Tucks the filter under the bumper.

 

[John Honcoop]

I did the rear end conversion on my f150. If you do it right you won't even have to bleed the brakes. drive line matched up fine. The 3.31 gear was for good gas mileage at highway speed. I get about 18.5-20 mpg's with my 3.31's. Not great for burn out's or drag racing but good for gas mileage. The backing plates are interchangeable for the brakes. If you pull the axles and you pull the calipers and brake lines off the axle itself all intact it will all go right back on the 9.75 without bleeding or opening the brake hydraulics at all. If you are running factory tire size the 3.73's will be nice. 3.90's are not a factory option but if you have a 2wd those will be great if you live in the mountains or an area with a lot of large hills.

 

[grantpa]

Hey John, thanks for the response and advice. The very best mpg's I got with my 3.31's was 16.5 on a road trip. I've NOT been able to duplicate that since-even on the exact same trip!!!
I avg about 14.5 now, hwy. City mpg is abysmal.
So my 8.8 backing plates/rotors, etc. will bolt on to a 9.75? Just as long as they're both coil-sprung, standard suspension?
All that'll be different is the driveshaft joint?

 

[98eb5.4]

very early 9.75 rear ends had 8.8 sized axles & for a few years, lugs were 12mm then went 14,

driveshaft length is not the same, factory limited slip feature may (or not) be relevant