whats my rear axle?

[playinwitmatchz]

Ive got a 2000 2wd reg cab longbed stick. What rear axle should i have? Gotta do the fluid in it soon, what should i use for brands for heavy haul, dont need my diff fluid breaking down on me. Also, can i swap in an axle from a 350 dually, or better yet 450 or 550? Its gunna be a hauling truck since thats what the ol 7.3 was built to do. Also, what fluid can i use in my tranny, zf6 and i have a cooler in the front, can i use synchromesh? or is it atf for me

[Fred Swanson]

Should be 3:73 gears, I would think you could put in the f-350 rear with a 4.11 gear ratio if need be....not sure about your manual trans fluid....Fred

[Zaairman]

You have the 10.5 Sterling (holds 3.5 quarts) and your ZF6 takes Mercon ATF.

[playinwitmatchz]

I know i have 4.10 gears. but am i really stuck using atf? 2nd is a bit notchy and ive heard good things with syncromesh or the various equivalents solving that issue. I hear all the time people running redline, royal purple, etc etc and switching away from atf, is this alright?

and does anyone know the dimensions and spring perch placements on the dana s110 axles from the 06 and up ford f550s? i would love to toss that in there since it could handle heavy loads without issue, but if its ridiculous to get it in there ill just use a dana 80.