Freaky 8.8 / 7.5 hybrid axle?

iwfur25 · Feb 7, 2016

Has anyone ever come across an 8.8 axle that takes the wheel bearings and seals from a 7.5?

I just got done putting a TrueTrac diff in so I know the stuff in the middle (carrier bearings, ring gear, shim pack) is all 8.8 or else that wouldn't have exactly fit right. So I go to put the new wheel bearings and seals in and they are way too big. Timken 6408 (bearing) and 8835S (seal) are supposed to be for an 8.8 so that's what I got.

The old bearing is a Torrington DB-59722... which matches up to a Timken 5707. Which is for a 7.5 axle. WTF. :annoyed:

The truck is a 2001 4.0 V6. It has the door code for a limited slip axle but totally didn't have one. I guess maybe the axle broke on a previous owner and it got replaced but that still doesn't explain the bearing size problem

85_Ranger4x4 · Feb 7, 2016

28 spline 8.8's like what Rangers and a lot of Mustangs have use the same shafts as a 7.5. They might play with length between some years though.

RonD · Feb 8, 2016

Yes, the 7.5" and 8.8" Ranger axles had the same tube diameter(2.80 inches) and axle shaft diameter(1.21 inches), up to 2010 when they got rear disc brakes and both got larger tubes but stayed same axle diameter.

Explorer 8.8" had larger tube(3.25 inches) and axle diameters(1.32 inches)

Good read here on the 8.8" with some comparison with 7.5": http://www.therangerstation.com/tech_library/Ford-8_8-axle.shtml

adsm08 · Feb 8, 2016

It's not "freaky" so much as "standard issue" on the Ranger 8.8s. All the 2.8 spline units should share end bearings and seals with the 7.5.

4x4junkie · Feb 8, 2016

I'm guessing this is perhaps another case of trying to identify parts using an auto parts chain store's look-up computer... Because those things are just riddled with errors.

Indeed, the 7.5" and 28-spline Ranger 8.8" do use the same shafts, bearings & seals (they are even interchangeable). The only freaky thing here is the store's computer (and the idiot who programmed it).

85_Ranger4x4 · Feb 8, 2016

4x4junkie said:
The only freaky thing here is the store's computer (and the idiot who programmed it).

And Ford's semi annoying habit of mixing and matching crap. This can not always be this, sometimes it might be that even though it is called this. :tease:

4x4junkie · Feb 8, 2016

Yeah, maybe... I could understand on something like a recent one-year change of an oddball engine sensor or something, but when there has been no variation in a commonly-replaced part of a major assembly such as the rear axle over nearly two decades ('90-'09, leaving them plenty of opportunity to correct such error), it's a bit less forgivable.

iwfur25 · Feb 8, 2016

Yeah, pretty much a computer listing issue. Rock Auto basically just calls out 8.8 or 7.5 ring gear. A few bearings say 7.5 and 28 spline together in the description but the brain still says "I don't have a 7.5".

85_Ranger4x4 · Feb 8, 2016

Rockauto is bad about throwing everything a Ranger has had.

I have been shopping for stuff for my 1995 D35 and still have to fish through D28 crap although no 1995 Ranger had a D28.

pjtoledo · Feb 8, 2016

you do know there are some 8.8 axles with 31 spline shafts right? those have bigger bearings & seals to match the bigger shaft. you probably got the bearings for the wrong axle.

just checked the Rockauto site, a couple listings say the same bearing fits the 28 and 31 spline shafts. sorry RA, major fail.

adsm08 · Feb 8, 2016

Two points of order.

1) The listings for a "D28" in 95 and up are referring to the hybrid axle. It used the heavier D35 outer parts, but was a 28 diff.

2) The 28 and 31 spline 8.8s share carrier bearings and pinion bearings.

AllanD · Feb 9, 2016

The FX4 Level-II trucks were the only ones that had the bigger axles and bearings.
But these are relatively rare...

So anything other than what the OP found would be considered "oddball"

Freaky 8.8 / 7.5 hybrid axle?

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