The most desireable axle which most easily "bolts-in" to a 91-94 Explorer, 83-97 Ranger, and 84-90 Bronco II, is the Dana 44 from an Early Bronco between the years of 71-77 (I believe). 66-70s are Dana 30 axles.
The most desirable from those years are the 76-77 as they came with disc brakes, rather than drum brakes. They do however also come with the same "inverted Y" steering setup, so the steering linkgages from an earlier D44 are better.
Some came with 4.11 gears, so try to find one of those, rather than the more common 3.50.
So now that you have you axle...
You will also want the radius arm drop brackets and radius arms from an Early Bronco because you will need to use those.
People are also using the Wild Horses 3.5" lift variable rate rockcrawker coils with a lot of success. I'm not sure how much lift it provides for an Explorer/Ranger/?BII though. I would guess around 6" or so. Those coils should sit right into the coil bucket.
You will also need a trac-bar aka panhard-bar for the front. This requires a bracket to be made to mount on the driver's side frame rail around where the steering box is. I have never seen a bracket "bolt right in" which means a small amount of frabrication. Or you could buy one designed for Early Broncos and modify it.
Now you need to mount shocks. You can get them so they mount in the stock location. I've heard 6" lift shocks work with the 3.5" bronco coils.
You will now have a different bolt pattern in the fron (5 on 5.5) than the rear (5 on 4.5). So you must also do one of a few things to clear that up.
1. Get two new wheels (with different bolt pattern) for the front and keep the ones in the rear.
2. Get custom rear axleshafts made for the rear with the 5 on 5.5 bolt pattern.
3. Get some wheel adapters (my least favorite choice).
4. Swap in the 9" axle that came from the same Early Bronco that you got the D44 from (my favorite choice).
So there you go. Go to this site down here and take a look It should help a lot.
Nobody's D44 Swap Page
