Been doing a lot of research and finding little to no data on what specific options drive the 9.75" diff. Trying to figure out if a 145" wheelbase 4x4 with a 5.0, tow package, and 3.73 comes with a 8.8" or 9.75". If anyone has this combination please chime in with what you have. Here is what I learned so far.

All 2.7 ECO come with a 8.8"
3.5 ECO with Max tow comes with 9.75"
Raptor comes with 9.75"
Have found some 3.5 ECO and tow package with 8.8" and 9.75", so not sure what drives which here.
5.0 with 3.11 or 3.55 comes with 8.8" regardless of tow package.
5.0 with tow package and 3.73 ???

 

That combination, if it is an electronic locking differential, will have the 9.75" rear axle.

PS: I'm sure you meant 8.8" not 8.5"

 

Oops. Only own two of them, you'd think I could get it right. Post edited.

Aslo: You base that on your truck or ??

 

My '18 has that combo (145", 4x4, 5.0, 3.73, tow package, e-locker) and has the 9.75".

 

Thanks gents. I can't believe that neither ford or three different dealerships can answer that question.
This pretty much settles what I'll get then. If I can get the 9.75" with a 5.0 I'll go that route.

Areaman, Can you elaborate more on your combination? What trim level, options, GVWR, payload, and epa mileage ratings? I'm really hoping I can tow without further mods. It will be close.

 

Not sure on the 2018’s but all previous 5.0 had the 8.8 just like the 2.7. All 2015 - 2018’s with 3.5 Eco have the 9.75 diff.

I do know that the 2018 2.7 towing pkg and heavy payload pkg comes with the 9.75 diff so maybe the 5.0 comes that way also for 2018?

 

Both my trucks have the 9.75.... My 2015 has locker, my 2018 does not

 

I don’t really see a lot of posts with people breaking their rear ends. Is the larger diff that important? Its nice to have but I wouldn’t go out of my way to get it.

 

All 5.0s that I have seen have the 8.8 regardless of tow package. Only 9.75 I know of are being reported here with guys having 3.73 and parts counter seems to confirm. Not sure about payload package.
I have yet to find a 2.7 on the lot with 9.75 regardless of tow package, however, maybe another way to get one?
I have seen some 3.5 Eco with the 8.8. Not sure, but I'm thinking it take tow or max tow to get it.

One thing is for certain: This is a significant upgrade and Ford is quite cryptic about the various ways to get it. One has to wonder just how much money Ford loses by not making option availability clearer. Just this forum has countless examples of people wanting features but not knowing how to buy them.

 

And to put more problem to your quest, my 2016 F150 supercab HDPP 5.0, 3.73 has a 9.75 HD ,2603 pounds payload, it is not as the regular 9.75 and have one liter more oil in it......I've red it has a beefer ring gear ...but found no confirmation of that, but in the ford spec it has a 9.75 HD diff.......why make life simple.