Interesting info on F250/F350 rear axles. UPDATE 01 24 14

dadwolf2 wrote:
DJ, I like your truck... but you need to add in your truck signature what rear axle you have because right now I'm still confused!! : )

373 10.5" Sterling

DJ, I like your truck... but you need to add in your truck signature what rear axle you have because right now I'm still confused!! : )

I'm not so sure about the Dana 80 under a SRW F350 (cab/chassis model maybe?). AFAIK these SRW axles never came in the metric bolt pattern and were more popular on some manual transmission Ram's although people report finding them under some E350's with the SAE bolt pattern.

OK, finally found the guy who knows present Ford diffs at the Ford Dealer!!!

The 11.5" is made by Dana. A Dana 80. But Ford stopped using the Dana 80 in SRW trucks on March 24, 2010. The reason is that the parts for the Dana are twice as expensive as the Sterling. There may be some 2011 model year trucks with the Dana depending on how many were still in stock when they ended the contract.

Now, both F250 and F350 SRW's get the same 10.5" Sterling rear diff. The only difference between the 250 and 350 is the 350 has a stiffer spring rate.

The F 350 Dually still gets the 11.5" Dana.

kohldad wrote:
While both the 10.5 and 11.5 may have the same GAWR, if you check deeper I'm sure you will find this is due to the tires limiting the GAWR. However, if you check the manufacturer's rating for the axle, you will see the 11.5 has a higher capacity. Axles are also have a torque rating though that info is usually very hard to find.

On my Dodge, the 11.5 GAWR is 6,190# due to tires yet the axle itself is rated for 10,300#.

AKSuperDuty, sure do wish they still used Dana axles but haven't for a few years. The quality of the Dana was worth the little extra money, but when you are selling thousands of trucks, the dollars add up quick.

Dead on. AAM rates its axles and wheel bearings for the 11.5 axles used in 2001 and later GM trucks and 2003 and later Dodge trucks at 10,900 lbs.

As Ford states "Gross Axle Weight Rating is determined by the minimum component of the axle system (axles, computer-selected springs, wheels, tires) of a specific vehicle. Front and rear GAWR's wiill, in all cases, sum to a number equal to or greater than the GVWR for the particular vehicle. Maximum loaded vehicle (including passengers, equipment and payload) cannot exceed the GVW rating or GAWR (front or rear)."

With trucks it is the tires and that is why the easiest way to increase the load capacity is to add two more tires so that four tires are supporting the load.

~DJ~ wrote:
I searched and searched but could not find a Sterling 11.5 either. I wanted to compare the weight capacity specs against the 10.5 for myself.

The only mention of it was on The Diesel Stop where one guy mentioned "the new Sterling 11.5".

I'm going to keep digging. Maybe this parts guy was all wet. I need to run down one of the truck mechanics at Ford!!!

Well I wont say hes all wet-just not sure what hes referring to-but theres is NO such thing as an 11.5 Sterling axle in a ford.

specifically speaking FORD and specifically comparing the Ford 10.5 Sterling axles used in F250/F350 Single Rear Wheel trucks-
99-05 identicle Sterling 10.5 axle
Beginning 2005 however, the Sterling 10.5 used in the F350SRW has larger 37 spline axle shafts. The F250 Sterling 10.5 has 35 spline shafts. I havnt capicity specs, I assume larger shafts would increas numbers.
2007-2010 Bearing change
2011 + 10.50 w/ 37 Spline (not sure what changed/ rebuild parts different?)

https://www.fleet.ford.com/truckbbas/topics/2011/2011_SD_Pickup_specs.pdf
page 19 of pdf file (page 73 of document) shows rating/axles used.

There are some other variations (pinion gear count etc) but basically, '05 up F350 has stronger higher rated rear axle though its still a Sterling 10.5.

FYI The Dual Rear Wheel F350up is a different truck-coming with a dana80 11.25 (however there ARE some F350 DRW's with smaller 5.4L gas engine that have the Sterling 10.5)

Since my 250 diesel had the camper package with overload springs, the only difference from same era 350 was the wheels and 4" axle block instead of my 2".

Things are changing. Look at the new Ram 3500 SRW verses 2500 and you will see bigger differences. However, I still feel the manufacturers could eliminate one SRW model and still meet the needs of all their customers by offering different GVWR packages.

Seems like an awful lot of trouble to go to, just for the sake of winning the "F250 is just an F350 SRW minus two leaf springs" argument...

While both the 10.5 and 11.5 may have the same GAWR, if you check deeper I'm sure you will find this is due to the tires limiting the GAWR. However, if you check the manufacturer's rating for the axle, you will see the 11.5 has a higher capacity. Axles are also have a torque rating though that info is usually very hard to find.

On my Dodge, the 11.5 GAWR is 6,190# due to tires yet the axle itself is rated for 10,300#.

AKSuperDuty, sure do wish they still used Dana axles but haven't for a few years. The quality of the Dana was worth the little extra money, but when you are selling thousands of trucks, the dollars add up quick.

Try the http://ford-trucks.com site. It's the place to go for Ford truck info.