Repair-It

Turns out the soaked right rear wheel/tire was the axle seal. I think this was catalyzed by parking it in a new spot, on a slant, tipped toward the right side, which wasn't doing the 25 year old axle seal any favors.

This theory was kind of confirmed because the bearing/axle was in good shape, meaning a worn bearing didn't cause the seal to fail. Given the mileage, this checks out.

Pics later, but steps go like this:

- Jack up, pull wheels
- Pull diff cover and drain axle
- Pull drum. This required a little heat and lots of wiggling. Would have been helpful to back the adjuster off but the wiggling method worked.
- Remove lock shaft bolt from diff carrier. This diff is like identical in design to the GM corporate axles. I don't think it's posi (pics later)
- Pull out lock shaft enough to clear axle shafts
- Push axle in and remove C clip
- Remove axle
- Disassemble drums (shoes were soaked so they need to be replaced)
- Pry axle seal out using the C clip end of the axle shaft which works easily
- Install new seal and the rest is the reverse of disassembly
- Anger and laziness kicked in - we didn't touch the left rear drum

It took a tad under 2 quarts, 80W-90. I used 75W-90 because that's what NAPA had.

Ford 7.5". I can't tell if this is a posi carrier. It could be an Auburn, with the back of the axle spider gears acting as a clutch on the carrier housing. Hard to tell.

If it was posi, wouldn't it have preload springs with plates in there? I think this is an open diff. It behaves like one anyway.

kevm14 wrote:If it was posi, wouldn't it have preload springs with plates in there? I think this is an open diff. It behaves like one anyway.

Was there a tag on the axle? If so, there are some numbers that correspond to the axle type/part number, gear ratio, and if it has limited slip. Plus other stuff like build plant and date.

You care about the lower line of characters. If it is something like 3 L 73, that's a limited slip 3.73:1 ratio axle. No L means no limited slip. The next number over is the ring gear size, you should see 75 for the 7.5".

There is a tag. I did not look at it. But it's an open diff - did you see the picture?