Wrong, the pre 92 10.25s had a shorter spline on the pinion that caused the pinion nut to loosen up.

After 92, they lengthened it, not a lot, but enough.

The 10.25 and 10.5 share the same diameter pinion gear. The ring gear size is the difference by .25 inch.

The 10.25 uses a thicker pinion bearing at the head of the pinion as seen here


They use the same carrier, and carrier bearings.









I'm sure it could be a 10.25 under that excursion. Ford did weird things on some model years. Being its a 2000, it could have got a axle off the super duty pile for the 99s. It doesn't really matter. Mine has 10.25 gears in it, a 10.25 LS, and a 10.5 pinion yoke. The difference is really just .25 of a inch on the ring gear.

Also, yes, you have a limited slip in your rear axle.

 

I knew one was shorter but I guess I was thinking of the larger yoke but the 10.5 pinion does appear thicker in diameter. And wasn't that pre '99?
http://image.fourwheeler.com/f/96191...ine_length.jpg

 

92 and earlier is short pinion.

Ford 10.25 & 10.50-Inch Axle Tips - Four Wheeler Magazine

 

Actually shorter IS smaller.

 

Shorter splines has nothing to do being smaller. The diameter and the pinion gear size from splines to the head is the same. The ONLY difference is the length of the splines. That's not really a smaller gear...

Found under: '85-'92 F-250 and F-350
Type: Full-float, semi-float (depending on gross vehicle weight)
Weight (lb., approx.): 310 (single wheel), 330 (dual wheel), 258 (semi-float)
Ring gear diameter (in.): 10.38
Pinion shaft length (in.): 10 1/8
Pinion shaft spline count: 31
Axleshaft spline count: 35
Axleshaft diameter (in.): 1.5 (at the splines)
Hypoid offset (in.): 1.50
Gear ratio range: 3.08-7.17

Found under: '93-'98 F-250 and F-350
Ring gear diameter (in.): 10.38
Pinion shaft length (in.): 10.50
Pinion shaft spline count: 31
Axleshaft spline count: 35
Axleshaft diameter (in.): 1.5 (at the splines)
Hypoid offset (in.): 1.50
Gear ratio range: 3.08-7.17

Found under: '99-'05 F-250 and F-350
Type: Full-float
Weight (lb., approx): 333 (single wheel), 348 (dual wheel)
Ring gear diameter (in.): 10.50
Pinion shaft length (in.): 10.50
Pinion shaft spline count: 31
Axleshaft spline count: 35
Axleshaft diameter (in.): 1.5 (at the splines)
Hypoid offset (in.): 1.50
Gear ratio range: 3.08-7.17



The 93-99 10.25 and the 10.5 can use the same pinion yoke.

 

OK you win.........shorter,

 

But only briefly

What's the thing just left of the ring gear that looks like a tone ring or something?

Nerdily fascinating thread, this. Reminds me I need to crawl under my rig n double check the tag.

 

LOL indeed it is

 

It is a tone ring. It runs your speedo

 

It is the tone ring which is the only major change in rear ends for decades (or forever). That ring gear is very thick so is probably is a 4:30 ratio. Makes me want to lick it....lol

 

Well you guys did it, you happy? You got me to go out and get under my Ex with a wire brush, curiosity got the best of me LOL!

So from what I've learned here looks like I have on my 2000 v10 4x4 a:


Sterling
138 F model
3.73 with no limited slip
10.5"
Oct 18 1999

I would bet by that model from the way you guys talk that my axle came off the Superduty pile which led me to be curious to know what my build date was, when I opened thedoor to check that all that was present was a white square with the word "void" all over it like it had been peeled off! Any way to decipher build date any other way? Figuring mine is an early 2000.

 

Not sure on alternative methods on the truck build date, but the axle is actually 9/18/1999 - "I" is skipped so J is actually Sept
A Jan
B Feb
C Mar
D Apr
E May
F June
G July
H Aug
I - skipped
J Sept
K Oct
L Nov
M Dec

 

Alright I got BOTH rear tires off the ground and got 4 1/3 turns on the yoke. So it's official right? I have a 4.30 LS axle....Please don't lick it, I don't know that i could ever look at my truck the same again.

 

Nasty, probably smells like dead---

 

Yes yes it did, smelled like rotten, metal gunky, poopy face....sorry i have young kids and watch a lot of cartoons.