I own a F150 Scad 8 ft box with HDPP ( 9.75 hd diff. ) I know there is one more litter of oil in the HD than the regular 9.75 .....why ???? both diff. housing looks the same size !!!
I've read somewhere in this site that there is 35 splines for the HD and 34 for the regular.....and the axle exterior wall are 1/4 in. and 3/16 for the regular.....is it real ?????
Some say there is a heavier ring gear. on the HD .....is it real.... Is there a real difference in gear quality between the regular and HD 9.75 differential ???? Couldn't find an answer on Ford site. What is HD in it ???
But Ford specify that there is a HD version of the 9.75 with the HDPP.!!!! Funny interrogation, isn't it ... Have a nice day

 

I can tell you that the axles and axle bearings are identical. I would like answers on the rest myself. I have a feeling that the only difference now may be the 3.73 gearset. In the pre 2015 trucks the axles were 7 lug on the HD.

 

Of what I know, you can order a 3.73 on a non HDPP F150 but the 9.75 HD only comes with the HDPP. And yes before it was 7 lugs.

 

You can only order the 3.73 with the 2.7 ecoboost and it comes with the 8.8 rear end. In the previous generation their were two versions of the 3.73 with the 9.75" gear set, not anymore

 

Do not want to be impolite but on Build my f150 site, I just built a f150 3.5 l with a 3.73 gear set for $400 ( Canadian site)

 

When I build a 3.5 with the 3.73 it forces the HDPP. Maybe its different in Canada but in the US you cannot have the 3.73 without HDPP.

I think i remember looking through the builders guide and the only difference they called out between the regular 9.75" and the HDPP 9.75" was the oil fill amount. Everything else was the same. Unless they downgraded the regular 9.75 axles from the 2014 to the 2015's I cannot imagine they changed anything. The old Max-Tow trucks with regular 9.75" axles had nearly the same GVWR(7700) and GAWR(4050) as the the new HDPP trucks.

 

I would like to know this too. I thought the only way to get the 9.75" diff on the 15+ trucks was to get the HDPP. But someone linked a ford spec book in another thread and according to it if you get the ELD you get the 9.75" diff and it does show a HD 9.75" for the HDPP. All I know which means nothing is the 9.75 on my 5.4 2010 looked huge compared to the 9.75 on my 2016 3.5EB.

 

I think you can build a 3.5 natural aspirated engine with the 3.73 but not the 3.5 ecoboost


The '12 + Raptor has a 9.75 gear set with 35 splines. The other 9.75 gear set is 34 splines.
I don't see anything on the Yukon website that shows any other versions of the Ford 9.75 gear sets being available. Based on this I will assume the HDPP 3.73 is the same 9.75 gearset as the non-HPPP versions. It's just that Ford forces you to get the HDPP to get the 3.73 where in the past you could get it with a "regular" payload truck

https://www.yukongear.com/diffdetail...c+%2711+%26+up

 

You can build a regular cab, 8' box with the 3.5 EB and 3.73's, but it adds the HDPP.

 

Or you can add the 5.0 and 3.73 and then get the 9.75 without HDPP
HDPP isn't available on a 502A anyway