So am I just misinformed but I thought 5.4's had the 9.75's? I started changing my rear axle shafts and realized it was an 8.8. Do they come with 8.8's from the factory? Or was the rear end replaced by the previous owner?

 

How many bolts for the cover? If 12, it is an 9.75.

 

if you have a 4r70w than it's most likely an 8.8. a 4r100 than a 9.75.

 

My 2000 F150Supercab 5.4L 4x4 had 9.75 rear and 4R70W. My current 2002 has a 4R70W. Haven't verifyed the rear but I'm sure it's a 9.75.

The 4r100 only came in the Lightnings I believe.

 

The 4r100 came on the Lightnings AND the 7700 option as well as the snow plow option. It also came on all Eddie Bauer Expeditions.

 

I may be misinformed, but I thought all 5.4's came with 9.75's except in the 7700 and F-250LD, which had a 10.25.

 

that is true. if he has an 8.8 someone has done some swapping.

 

If it has the 8.8 then someone ether swapped in the 5.4 or swapped in the smaller rear!
5.4 came with 9.75 rear.

Phil

 

What is the 8th digit of your VIN? L,M,W or 6?

.

 

Ok, so its got 12 bolts on the case but I put new axle seals in and It took the 8.8 axle seal, the 9.75 was way to big? I'm stumped on what axle I have. Not sure of the vin but the axle code on the door sticker is H9 I'm pretty sure. Also, unless the clutch plates are completely gone its got no limited slip. Is there any way to tell by looking inside the case with the diff cover off?

 

12 bolts = 9.75. Take a look at this thread too. https://www.f150online.com/forums/ot...-bearings.html

 

Round diff cover = 8.8
Sideways egg shape = 9.75

 

This article explains a lot about the 9.75. http://www.fourwheeler.com/techartic.../photo_17.html


.

 

I just copied and pasted this from my thread. Basically your truck has a 9.75 rear with a smaller style axle. The 8.8 bearings work fine since the axle is the same as the 8.8 axle but with 34 tooth spline. Hope it helps




OK, I think I solved it. Axle cost me $240 from ford cuz they were the only ones that had an answer. All of the other parts stores offer 1 axle for the 9.75 and for the 8.8.

The ford tech used my VIN and told me that the tag on the rear end (had i not tossed it) indicated 3.73 gear and 9.75 locking. Also, it said 923A which I guess is the code that says that I have one of the few trucks with a different axle and bearing setup. My trucks takes (driver side) a F75Z4234MB axle. This is identical to the 8.8 axle except it has a 34 tooth spline instead of 31. 99% of F150's with the 9.75 use a F75Z4234LB.

So, I hope this helps anyone with this problem in the future. If you have a 9.75" rear end and the replacment bearings are way too big and for some odd reason the 8.8 bearings fit.......you have the above axle. You didnt get the wrong parts, nobody swapped the motor or rear end when you weren't looking and my personal favorite.....Ford didn't throw in some old parts that they had laying around. For one reason or another ford used a smaller diameter axle on some 9.75 rears from 97-mid99. They switch to the other axle in mid 99.

 

Why does it appear that the OP has the same issue with an 01?