Narrowing the Ford Explorer 8.8 is not necessarily a "weekender" project, but it is very simple. This write up is ONLY intended as a guide for competent, trained individuals, capable of performing the job. You should be skilled in measuring, cutting, and welding. If you are not, you should not be doing all of this.
Before you get completely discouraged, you can perform a few tasks to chop off the price tag. If you are not a trained welder, capable of proficiently welding the axle tubes together (and making them hold), but you can measure and cut, you can perform the disassembly, cutting, and re-assembly. You will just have to source an experienced, or professional welder to take care of that portion.
***If you are not comfortable with any portion of this job, DO NOT DO IT. Find someone who can. Major damage and safety are at risk if you complete this job incorrectly.***
First, you need to source the correct rear end for this job. Please read the Prelude section
Click on Images Below to Enlarge
Before you can cut or narrow anything, you need to strip it down. Start by placing the axle assembly on a set of jack stands, or structurally sound support. You do NOT want it to fall, or roll off. Invert the axle and drain whatever remaining oil is inside of it.
After the diff has been completely drained, remove the brakes, rotors, and all hardware.
Remove the brake lines as well. There are no pictures of this step. Removing brakes is pretty self explanatory.
Flip the differential "open side" up to access the differential assembly. This is what you should see with a LSD.
Remove the spider cross pin bolt with a 5/16 or 8mm wrench. The pin should slide out easily just by pushing it from either side.
Next push one axle inward toward the center of the differential. The C clips may fall right out, but may also require a little nudge with a screw driver or long tool to push on them. Once the C clips are removed, slide each axle out. Once the axles have been removed, you can remove the backing plate.
For this write up, the perches and sway bar mounts have been completely stripped. There are a few ways to remove perches and mounts. Torches, cut-off wheels, plasma cutters, and more. Personally, I feel the job can be done quickly with a cut-off wheel. The likeliness of scaring up the tubes is lower, and the cleanup is quicker. After trimming off as much as you can with the cut off wheel, clean it all up and smooth with a flap disc or sander.
Each axle tube is a different length.
The left side tube measures 19 15/16". The right side tube measures 17 1/16"
The difference is 2 7/8". This is the amount that needs to be removed from the left side tube.
You are now ready to start measuring for your Driver's side cut that will narrow the axle tube.
You need to be careful where you make your cut. For instance, our build requires us to keep the vent fitting (though it can be relocated), and the factory brake line retainers. There is not enough room to make the cut, so we must mark these out as areas to avoid when measuring.
The inner section of the axle tube has barely enough space to make the cut. However, there will be a lot of weld in that area which may weaken the tube. Generally speaking, it is also a very poor area to work in being so cramped, or with little area to work in, prep, and weld. The probability of failure is higher in this area. We marked it off the cut list.
If you look at the outer section of the tube, you will notice it tapers. There is not enough to cut out here, nor is it a good idea to stress a weld this far out. This was marked off as well.
That leaves us with this much space to make our cuts.
Before you put your marker away, grab a straight edge that will sit parallel to the tube (such as angle iron, or any 90 degree bent straight edge). Mark a straight line as a "clocking reference"
**NOTE - The reference line will show you which position the axle tubes will sit after you cut them and stick them back together. **
Now you are ready to mark your cut. Virtually anywhere within the marked section will do, but you should try to avoid cutting in the section where the spring perches or other brackets will be welded directly to. You should also not have the weld in the same position as a U-bolt as this will stress the weld.
Measure and mark your first cut. Rotate the axle and make a small reference mark about an inch apart until you have marked the first cut line completely around the tube.
Then measure from the same position, but add 2 7/8" to the first measurement. Completely mark the circumference of the tube as you did with the first measurement.
An excellent guide to making straight cuts is masking tape. Place the edge of the masking tape up to your cut line. DO NOT place masking tape on the same sides of the cut lines. The area in between the tape should be exactly 2 7/8".
>>> IF YOU DO NOT HAVE THE CORRECT MEASUREMENT - MEASURE AGAIN!! <<<
It is wise to mark the tape with your cut side. This will help avoid confusion of where to cut the tube (or which side of the line to cut).