Did Ford ever use the 10.5" axle with drum brakes? I am looking at a used axle on Craigslist and the guys claims it is a 10.5" but said it has drum brakes. I thought Ford started using the 10.5" on the Superduties '99 and up and they all had rear disk brakes. Prior to '99, didn't ford use the 10.25" rear with drum brakes?

Thanks for the help.

 

The obs axles are a sterling 10.25 with drum brakes
The center section looks identical on the outside even uses the same cover but it is 4 inches narrower
Im a bout 99 % sure it's a sterling 10.25
Hope this helps

 

Not that this is relivent but I was told by a gear junky that you could even use the 10.25 guts out of an obs and put them in a 10.5 SD. So they must be real close in size, shape, and design.

 

Not that this is relivent but I was told by a gear junky that you could even use the 10.25 guts out of an obs and put them in a 10.5 SD. So they must be real close in size, shape, and design. So close they could have been mistaken, or not, who knows.

 

The bearings were different on the 10.5 but the diffs are the same physical size.
The 10.5 had a 3 pinion spider setup (I think) and the 10.25 only had 2.
If you're buying a locker it's the same one for both.

The e99 10.5 uses the same caliper on both sides... So ones in the front and ones in the rear of the axle. But 99 was start of disks.
Although, vans and the "larger then f350s" were usually behind on times, so it may be a van rear axle. Hopefully you'll get it figured out.

Best bet is to go over and measure the width like someone suggested. Superdutys are wider apparently.

 

Here is a link to a website that seems to have some good info. They try and explain the differences between the 10.25" and 10.5" axles.
Hope this helps.
Ford 10.25 & 10.50-Inch Axle Tips - Four Wheeler Magazine

 

IIRC 98 was the last year for 10.25, so any vans had a drum brake rear 10.5 that is the old 8x6.5 pattern.

 

My E99 as a 10.25.

Decodig the rear diff tag.

The codes on my rear differential tag are :
S409B
3L73 102 8C11

The break down of these codes:

S409B:
S = Sterling Differential
409 = Print Number (Model Number)
B = Revision Identifier (Change in Design)

3L73:
3L73 = 3.73 Ratio
L = Limited Slip
Absence of L = Open Differential.

102 denotes the ring gear size. 10.25 inches. 105 would be a 10.5 inch ring gear.

8C11 is the build date.
8 = year of manufacture. In this case it means 1998.
C = month of manufacture. A= January, L= December so C= March
11 = day of manufacture. So My differential was manufactured on March 11, 1998

 

Robin thats a new one to me...but you do have disc brakes right?

 

robin is yours a 350 or 250 my early 99 350 reads s409b
3L731058f22

 

Mine's a 250. Build date 3-98.

 

Thanks for all the great info guys. I emailed the seller back and asked about the possibility of him having a 10.25 instead of the 10.5 he advertised, he hasn't responded. My guess is he was probably confused himself. It seems that people get scared when they realize they are dealing with someone knowledgeable about what they are selling. Knowledge is power, and this forum has plenty of it. Thanks again!