The brilliantly engineered 8.8" axle in my Bronco is about ready to go. It's leaking gear oil around the pinion seal. I put a new seal in it yesterday but there is quite a bit of play in the pinon so I doubt the new seal will last very long. I also noticed a very slight clunking somewhere in the driveline over the last month or so and I don't think it's a coincidence.

So.... I think I'm going to swap a 9" axle in its place.

We all know the 9" is a way better axle. I'm going to have to rebuild an axle to put in there anyway, so why not do it right. This way I can continue to drive it (at least until it breaks) until I get the new axle set up and ready to go.

I am pretty surprised at the cost of parts though. It looks like an already-set up third member will set me back at least $1000. Since I am cheap but handy, I am thinking about setting up the gears myself. I haven't done it before, but I'm pretty confident that I can do it. There is a good tech article on how to set up the 9" gears. I will have a garage and a workbench to do this on, and I will take my time.

Also I am thinking about a powertrax locker. They get good reviews everywhere that I read. I am tired of the open differential in the rear and I don't want a full locker. I will probably get the axle powder coated black before I put it back together.

And I going with a gear change too. 4.10's in the rear for now, and the front will soon match.

 

What year is the Bronco? Is there going to be a VSS issue? There is a place here is So Ca (Brea) that makes VSS that mounts on the yoke of the t-case.
Too bad this was not a few weeks sooner. I just sold a 31 spline axle with a decent LS for 350 bucks. It was in a Bronco too.

 

It's a 90. I would only lose the ABS, which is junk anyway so I'm not going to worry about it. The pick n pull by my house sells axles and there are a ton of junkyards in the area. I shouldn't have a problem finding a donor for a good price.