I ordered a new set of Richmond 3.73 gears to replece my 3.55 ones because I changed tire sizes from the stock 235-70-16 to the max 265's. I was told that I have a 8.8 diff. I have a 2002 F150 w/ 5.4L triton. As it turns out I have a 10.25 diff under my truck which is wierd because Jegs as well as Richmond don't even make or carry gears for it yet. My door code is H9 which is correct but, doesn't the 10.25 only come in the 83-03 F350's and not F150's??? I'm confused! The guy at Jegs said I might have to wait for a year or two before they make replacement gears. does anybody have any info to why Ford put a F350 rear end in my truck?

 

No, you have a 9.75. It looks just like a 10.25. If you in fact DO have a 10.25 then I am floored, as well as probably everyone else in here. Never heard of it. Your info on the 10.25 is correct however. I know I have a 9.75 (and your's also) because I changed my diff cover and even though they look identical, the 9.75 and 10.25 have slightly different covers that will not fit each other. Also look on the tag attached to a bolt on your diff cover, it will tell you exactly. No codes to descipher or anything...it will say 9.75...

 

You have the 9.75 like Galaxy said (unless you have the 7700). The F350's have a 10.5 or maybe it's 10.75, has full floater hubs and has eight lugs. I think the cover has 14 bolts on it too??

The 10.25 is used on the 97-2000 Light Duty F250's that are now called the 7700 F150. It has 7 lugs and does not have that huge center hub that sticks out like the Super Duty rear ends.

 

Thanks for clearing that up for me. Now I can order the correct gear set.

 

Actually, now that I think of it....... If you have 4x4, your FRONT axle is a 8.8...........

Sounds like you have 4x2 anyway, but I just thought I'd toss that out there too!

Good Luck!

 

choochoo1968,

- 4.6 comes with a 8.8 rear axle.
- 5.4 comes with a 9.75 rear axle.
- 5.4 (7700 group) comes with a 10.25 rear axle.