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8.8 Swap

Explorer 8.8 Installation
Xtreme Performance

What you need to retrieve from salvage yard:

1. 8.8 rear from Explorer as described below
2. Driveshaft flange and/or aluminium driveshaft if you find one for less rotating mass. Stock S10 driveshaft can be used but will require the driveshaft mating flange from the Explorer driveshaft to be adapted to the S10.
3. (4) 12 point (12mm x 1.75 x 30mm) flange bolts to mount driveshaft to differential.
4. U-bolts from Explorer rear unless you will be installing lowering blocks.

What you will need to purchase from the store:

1. NAPA Conversion U-Joint part # puj 355
2. Brake line adaptor 1/4″ FNPT x 3/16” MNPT Dorman 43303 7/16-24 in inverted flare(female)
x 3/8-24 in inverted flare (Male), Weatherhead #C7828
3. Small cable loop (available at home improvement stores or hardware store)
4. Small Cable clamp (available at home improvement stores or hardware store)

We all have heard the Ford Explorer rear ends were similar in width and were supposedly a good match for the S10. This rear has a ring gear of 8.8 inches and is just as strong as a Chevy 12 bolt. They have massive 1.32″ diameter axles with 31 splines. On top of all that, the limited slip rears only come in 3.55, 3.73, or 4:10 gears. All 3 are pretty awesome gears for street/strip. If you find one out of a 1995-2002 Explorer it means they will have disc brakes. You can be upgrading strength, adding a posi, getting better gears, AND making a huge rear brake upgrade to discs all in one swap… can you imagine the money saved from doing that to your 10 bolt? I took some measurements of my stock
2wd rear from backing plate to backing plate (48″) as well as the spring perch measurements (38.5″).

I wrote this information down and went to the salvage yard to verify what people have been saying about the Explorer rears. I found a 2001 Explorer so I took the measurements and found that the 8.8 rear was approximately 4-1/2 inches wider from backing plate to backing plate and 0.5″ wider from spring perch to perch (Figure 1). Looks like this one will work.

Figure 1

What Explorer rears to look for:

1991-1994 versions had 10-Inch drum brakes, the 1995-2001 models come with disc brakes. All explorer rears have 31 spline axles from the factory making them very strong and a desirable swap for not only the S10, but the Ranger and Jeep enthusiasts also. You do not want to install the 8.8’s with the weak 28 spline commonly found in Rangers and Mustangs.

This is the tag that you will want to check before you purchase the rear.(Figure 2) This tag will tell you what internals the rear has. Check the bottom left hand corner of the tag. It may be a little difficult to see, but you can see that it says 3 L 73. The 3 73 is the gearing, so 3.73 obviously, and the L in the middle means that it is limited slip which is similar to a posi. If it had a space where the L is and it just said 3 73 then it would mean it was an open differential one wheel wonder.

Figure 2

The shock mounts from the S10 will need to be modified for the 8.8 U-bolts. The 8.8 has 3-1/4” tubes and the S10 rear has 2-3/4” tubes. The holes in the shock mount lower spring plate need to be
elongated outwards on a 45* angle to accept the 8.8 U-bolts. (Figure 3)

Figure 3

The Ford 8.8 is wider than the S10 7.625 rear. The distance between the Wheel Mounting Surface

(WMS) on the 8.8 I found to be 59-1/2 inches. The same measurement on the 2wd S10 7.625 is 54-
1/2 inches. 4X4 and ZR2 models have a wider stock axle than the 2wd. This install was for a 2wd. For
2wd’s, this can be made up in the backspacing found in different rims 7.5” backspacing for 10 wheels and 5.5” BS for 8” wheels. However Corvette and Fbody wheels are the correct backspacing. Or just leave it and have your rear tires sticking out a bit.

The leaf spring perches are only half an inch wider than the S10 leafsprings. The distance between the spring perches for the 8.8 is (38.5”) and the S10 is (38”). The distance from the driver side spring perch to the center of the location for driveshaft mounting on the 8.8 is 20-1/2 inches. On the S10
7.625 the distance is 19-1/2”. There is only 1 inch difference in offset between the explorer and s10 rears. (Figure 1) This means they’ll sit perfectly.


Jack the truck up and place on jackstands on the frame. Unbolt the S10 driveshaft from the rear. Disconnect brake line from the connection on the frame on the drive side. Disconnect the E-brake cable at this time also.

Remove the shocks from the shock mount. Disconnect the swaybar if equipped from the s10 rear. Unbolt the shock mount from the spring and remove u-bolts. Repeat for the passenger side.

With a jack under the spring, unbolt the spring from the shackle and lower it slowly. Repeat for the passenger side. Now slide the rear out from under the truck towards the rear of the vehicle. This was much more forgiving on the back than trying to lift it over the leafsprings.


Install the 8.8 in from the rear of the truck also and install the modified S10 shock mounting plates (Figure 3) to driver and passenger side of the 8.8. Once you have all the spring perches mounted, lift the leafspring back into the shackle and install bolt. Connect the shocks back to the stock mount.

To reconnect the swaybar to the rear, I purchased two 3-1/2” exhaust clamps. The swaybar bushings and brackets fit the exhaust claps with ease.

Axles and Rotors:

The Ford Explorer bolt pattern is 5×4.5″. The S-truck is 5×4.75″ meaning you’ll need to have the axles re-drilled to the S-truck bolt pattern or just pick up wheels with the Ford pattern. Take your axles to an axle shop near you and have the S10 bolt pattern drilled into the axles and rotors. Have them install the new studs at this time. Or if you want to drill your rotors yourself here is a write up on that procedure. I would leave the axle modifications to a professional.

Some Explorers came with Ford Racing (FRPP) aluminium driveshaft which is commonly found on the Mustang Cobras. Since you need to get the driveshaft mating flange for the rear, pick up the driveshaft too. Have it cut to length and install the adaptor u-joint at the yoke side of the driveshaft.

The 8.8 uses a pinion flange instead of a yoke like the S10 differentials. The stock Explorer driveshaft uses a 1330 style U-joint. Spicer makes adapters that connect explorer flange to the S10 1310 style U-joints. Dana Spicer P/N: D/S5-134X. Make sure to verify u-joint style prior to purchasing. This could have changed between years or there may be an updated version available. The driveshaft pinion flange (Figure 5) mounts to the 8.8 with 12mm x 1.75 thread bolts.(Figure 4) I would retrieve these along with the driveshaft when you pull the rear in the salvage yard. If you did not remember to grab these while you pulled the rear. The 12-point factory bolts are Ford P/N: N800594-S100. There are 4, and come in a bag of 4. Print the picture in (Figure 4) and take it to the dealership if needed.

If you are unsure how to install the u-joint you can take it to your local driveshaft shop with your S10 driveshaft in one hand and the Ford end piece in the other hand, and say “I need this piece (point to the end piece) put on this driveshaft (point to your S10 driveshaft) and I need the length to remain the same as the S10 shaft.” This is all that is needed for the driveshaft to work. I had my driveshaft the next day for $130 bucks. But I used the Explorer aluminium driveshaft I scored in the salvage yard for
less rotating mass.

Figure 4

Figure 5

Brake Line Connection:

Next item you will need to purchase is a break line adaptor. 1/4″ FNPT x 3/16” MNPT Dorman 43303
7/16-24 in inverted flare(female) x 3/8-24 in inverted flare (Male), Weatherhead #C7828 (Figure 6). Figure 7 shows the adaptor in the installed position.

Figure 6

Figure 7


I did not install the parking brake on either of my swaps since I am an auto. However if you wish to install the parking brake it should be fairly simple to accomplish. This is what I have found on the internet that should work.

If your 8.8 is a drum brake and you are installing it in a drum brake S10 the cable will install like OEM. If your 8.8 is a disc brake and you are installing in a drum brake S10, Pick up 2 small cable loops and 2 small cable clamps. Push your S10 E-brake cable through the 8.8 cable mount. Loop the cable around the caliper e-brake hook using the cable loop. Secure cable with the cable clamps. (Figure 8) The return spring may need to be ground down if it bottoms out before the E-brake engages.

Figure 8

8.8 installed in 2001 Xtreme Blazer.


A few pictures have been borrowed from similar write ups found on the internet.

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