Hello All,

I have an issue I am hoping you might be able to answer. I have a 2002 F150 FX4 XLT. I was hearing noise from my rear end and thought that one of my bearings was going out. After looking at my diff. tag it indicated that I had the 9.75" with 3.55 gears. The door tag indicates an H9 axle and from my research, this is an 8.8". Also, my differential cover is for the 9.75".

I purchased the seals and bearings for the 9.75". Once I pulled the old bearings out, it was clear that they were much smaller. I exchanged them for the 8.8" bearings and seals and they were an exact match.

While doing the job, I realized that the bearing wasn't the issue but the axle was bent and needs replacement.

I am confused as to what I really have. I have owned the truck since new and the rear end is original to the truck. Only because I want to be ridiculed, I will tell you that I had to install the new seals and bearings with the bent axle because I needed to get home from my Dads where I was working on it. But I still need to replace the axle and not sure what to order.

Any help would be much appreciated. I have looked here and other forums and can't find my answer. Sorry so long...

Thanks,

Jay

 

Jay,
note the your bolt configuration rear differential shape and compare to ford section in the link
Differential Identification | West Coast Differentials

 

Hi,

Thanks for the response. It is indeed the 9.75" 12 bolt cover but the replacement bearings and seals were 8.8".

 

H9 means 3.55 limit slip... It does not designate the size 8.8 or 9.75 ..........You look at the rear axle tag to get that.......... I have a H9 door code, and it has the 9.75 inch axle also.


I don't know for sure, but I heard at one time FORD made the center pumpkin 9.75 inch with the 8.8 inch size axle shafts and bearings......... later in life, the OB bearing sizes were increased... I cant say the year for sure.

 

I got the same thing when I replace the bearings in mine as well. Just that mine happened to be the larger bearings. I became a real "gray area" as to when this was being done. I suppose if the OP would find a drive line shop that they might shed some better light as to when this happened or why?

My unsubstantiated suspicions...theories are that they forgot to change or adjust the cutting tool while making these things, when switching from 8.8 to 9.75 and they just ran with it rather then going through the expense of reworking everything.

 

I also ran into the same problem when working on my 9.75" rear. I had to do wheel seals and ordered them from dealer and they still came in wrong, I had to go back and get ones for an 8.8

 

here is a description of the 9.75 axle with the "BIG" bearing... 1.7 inch bore and 2.98 OD ........ still no definition of WHEN the change was made.


https://www.ebay.com/itm/Alloy-USA-1...laWOaE&vxp=mtr