My understanding is the the 9.75 means the diameter of the ring gear which means it’s heavier duty.

 

Curious to know: Has anyone priced a complete axle replacement (part) with the 9.75" rear differential? I browsed the parts catalog, but cannot seem to locate the entire axle.

 

When I looked at fords parts site with my serial number ( f150 hdpp with a 9.75 in. HD, 3.73) the part number for the differential housing is near $750 I did not check for the whole axle. But both 9.75 and 9.75 HD diff exist.

 

Just to muddy the waters a bit more. FWIW.
3.5 Ego, 10 speed, 3:55ELD, 302A, all the trailer tow stuff except the bumper, SCab, 6.5 bed. 9.75 axle.
My '12 with 5.0, trailer tow stuff, SCab, 6.5 bed 3:55 open, 9.75 too.

 

How do I know which differential I have?

 

If you go see your seller with your serial number they will tell you. Or you might try using fordparts and you should get it.

 

Mike,

2018 701A Platinum Crew Cab 145", FX4, 5.0, 3.73 E-Lock, Trailer Tow Package, 36 gallon extended range tank.

From the door label:
GVWR: 7000 lb
Payload: 1586 lb

From the window sticker:
EPA 16 city, 22 highway, 18 combined

From the manual and Ford towing guide:
GCWR: 16200 lb
10,900 max conventional towing with weight distributing hitch.

 

I was hoping to be able to just crawl underit and see the difference. I just looked at the 2016 brochure and the only one that specifically mentions the 9.75” is the hdpp.

 

...

 

Thank you tmcolegr, I have the 9.75”, I found the tag with 9.75 and the back cover was the same as shown. I am not sure if it is the 3.5 eco or the max tow that gives the larger rearend. Now I am curious if that is the same axle housing as the hdpp has because if I understand it correctly that is heavier also with that package.