How To Convert A First Gen Explorer to 4WD

[MrQ]

I had some time so I figured I would get this 'how-to" rolling.

Disclaimer: I, Dan Jones, am not in any way liable for how this tutorial is to be used. I am also not liable for any, accidents, problems, or issues that develop from using this tutorial. All precautions should be taken first before attempting this type of work on a vehicle. Please be careful.

Post 1: Important Information and Intro
Post 2: Front Suspension and Axle
Post 3: Transmission and Transfer Case
Post 4: Rear Axle
Post 5: Finishing Up


The 4x4 swap on a Explorer is a straightforward if time consuming process. It is not easy, nor is it economical. Fortunately, most of the conversion can be done in stages if you need to have your truck running during the swap. In this thread I am going to deal with a 4wd conversion on a 2wd Auto (specifically, Red)

The beginning specs on my Explorer when I started:

1994 XLT
2wd I-beam setup
2wd A4LD transmission
Ford 8.8 rear axle w/ 3.08 gears

Info you need to know first!

Axles:
There are two axles on a 4wd swap:

The front axle, the D35 Twin Traction Beam

and the Ford 8.8 rear axle

YOU MUST USE THE SAME GEARS FRONT AND REAR!! Ignoring this warning will turn your transfer case into a boat anchor.

Compatible Ford gear ratios for the D35 from weakest to strongest.
3.27 (relatively easy to find)
3.55
3.73 (Very easy to find)
4.10 (Difficult to find)

(Since the 3.08's were never used in ANY front D35 axle my rear axle had to go.)

If you are going to be wheeling this rig hard, I wouldn't go any less than a 3.73. A 3.27 is a pretty wimpy setup and a 3.55 is decent. Its a choice on your part, deal with a smaller gear ratio to match your rear gears to save money, or replace both front and rear axles to get a better ratio. In my case I didn't have any choice, but even if I did I still would have gotten the shorter gears.

Also at this phase you have the choice of going with manual hubs, if your D35 does not already have them.

Don't underestimate this part of the swap. It is not easy, but it does give you a lot of openings to replace hard to get to parts, so take advantage of it.

Hubs:
Hubs are the link that connect your front wheels to the axle. With them unlocked there is no power to the front tires, locked you are in 4 wheel drive. There are two types of hubs for the D35, the Warn Manual Hubs made for Ford and the Ford Automatic Hubs. The hub is supposed to be the weakest link in the 4x4 drive line. It is designed to break if too much stress is put on the axle, making it a failsafe against expensive breakage.

A manual locking hub is pretty much what it says, you have to get out of the vehicle to manually lock or unlock the hubs. The original Ford manual hubs are much stronger than the auto, but lack convenience. They are also much less of a maintenance issue than the autos.

The Ford Auto hubs allow the driver to stay inside the vehicle while using the motion of the front axle to lock and unlock the hubs. This is convenient, but requires more parts to make it work. Over a period of time these hubs can get gunked up and start chattering, locking and unlocking the front axle, and causing all sorts of disturbing sounds. If the maintenance is not done regularly the internals will wear out quickly. It is also physically weaker than its manual counterpart. Most people switch to the manual hubs after their autos break.

Transmission:
This is another hiccup in the road to 4wd eliteness. As always, you have a choice on what transmission you want powering your rig.

First is the A4LD Auto. It is a decent tranny, but not overly reliable. It is meant to do one thing, and one thing only: push a 5300lb SUV down the road with stock tires. You start adding larger rubber and bigger gears, expect to beef up this transmission as you go along or you Ex will be hemorrhaging ATF at your next trail run.

The next choice is the ol' reliable M5OD manual. Once you put this in and follow basic maintenance you will be set for the life of this truck. One problem, if your truck is not a manual to begin with, expect to lose a couple years off the end of your life getting it in.

Now this is a clarification for everybody on these transmissions: A 2WD A4LD OR M5OD WILL NOT WORK WITH A TRANSFER CASE. No if, ands or buts. You MUST replace the tail shaft with one from a 4WD. It is better in the case of a the A4LD to get a 4WD rather than trying to convert the 2WD. The 4WD has a deeper pan and bigger filter to compensate for the extra stress on the transmission.

Transfer case:
The transfer case is integral to making your 4wd system work, and personally my favorite part of the drive line.

You realistically have only one choice: the Borg Warner 1354 Manual transfer case. But as if in penalty for the simplicity of this decision you now are headed down the path of actually finding one! These are getting very scarce as they are constantly being used to replace the electric 1354 (more on that later). If you find one in a junkyard, grab EVERY piece associated with it, arm linkage, shifter, boot, electrical harness for the dash lights, and floor plate. If not you will be on a perpetual hunt for each of these items. Be prepared for a wait.

In honorable mention is the BW 1354 Electric. There is one problem with this case and only one. The shift motor. It is a rather expensive piece to replace when it goes bad which does tend to happen often. This is not a realistic choice for a 4wd swap. To get it to work you would have to delve into a whole lot of electrical wiring and schematics to get it to work and buy a lot of extra parts. BUT, if you can stand getting down under your truck every now and then to switch it into gear, then grab it and the SHIFTSTER (http://theshiftster.com/) and get 'er done.

Driveshafts:
Oh yes, you are not done yet. You still have to get power to those new axles. As you may already know, there are two drive shafts with a 4wd setup, a front and a rear. And yes, they both must be had.

A 2wd drive shaft is aluminum and uses a slip joint to attach to the tranny. The replacement is steel, made to fit the transfer case and expandable to fit 4 door's and sports. It will also work with the M5OD as well as the A4LD. Nice of Ford, aye?

The front drive shaft is also steel and is expandable. It bolts to the transfer case through a double cardan joint. (http://www.4x4wire.com/toyota/maintenance/tacoma_4runner_30k/double_cardan.jpg) It's basically three universal joints piled together to make a strong joint. Anyway, at the JY grab all the bolts off of both ends of the drive shaft.

Miscellaneous:
Yes there are miscellaneous parts.

You will need a longer 4x4 speedometer cable, 4x4 rotors, transfer case skid plate, 4x4 drivers side drop bracket and other parts I have forgotten.

AGAIN, I will reiterate this is NOT an easy or economical swap. With that in mind let's press on.

Parts Needed:
D35 front end
4x4 tranny of your choice (and associated parts)
BW 1354 transfer case
Rear axle (possible)
Front drive shaft
Rear drive shaft
4WD speedometer cable
4wd rotors
Transfer case skid plate
4wd drivers side drop bracket
All associated nuts and bolts
Transfer case shifter
All vent tubes for tcase, tranny, front, and rear axle

Parts that would be nice:
Shifter boot
Electric harness for manual tcase
Manual locking hubs

Next up:
Stage 1: Front Suspension and Axle.

 

[MrQ]

Stage 1: Front Suspension and Axle

The parts required for a front end swap are as follows:

D35 TTB with gears matching your 8.8
4x4 Rotors (calipers are the same)
4x4 Coil Springs*
4x4 Driver's side drop bracket
4x4 drag link
4x4 tie rod ends
4x4 inner tie rod
4x4 bearings
4x4 drivers side bump stop
Auto or Manual Hubs
(If you choose to convert the front hubs to manual)
Spicer kit pn# 28068X - 4wheelparts.com


Additional hardware
4x 1/2" x 1 1/4" GRADE 8 bolts and nuts (Needed)

(Optional)
Radius Arm bushings (Optional, but a good idea)
Pivot Arm bushings (Optional)

Tools required
Full set of Metric sockets 10mm-19mm (Deepwall if you have it, as well)
1/2" breaker bar and ratchet
3/8" ratchet
Cut off tool with extra blades or grinder
Air Chisel/Hammer (VERY helpful)
At least two 2ton jack stands
A decent jack
Sledge (if you have it)
Tons of PB Blaster
1 1/8" wrench
Pitman arm puller
Propane/Butane torch
1/2" Impact wrench (Not necessary, but very nice)
Safety glasses
Tough work gloves
Drill with assorted hard bits
Level

*The 2wd coils can be reused. The 4x4 coils just have a stiffer spring rate.

Prep work
Spray PB blaster on the coil nuts, radius arm bushing nuts, drop bracket nut, and shock nuts.

Removal

1. Put the Ex on jack stands. The best place is under the radius arm cross member. Remove the tires, calipers, shocks, sway bar (at the I beams) and cut your ABS cables to the sensors. (Yours probably doesn't work anyway, right?) Hang the calipers out of the way, don't let them dangle on the brake hose. You can remove the rotors if you want, but its not necessary.

2. Jack up each arm as you do this. Make sure you steering wheel is centered. Lock it in place. Now remove the tie rod ends from the knuckles with the Pitman arm puller and then do the same with the drag link on the Pitman arm. You will be unable to reuse any of these parts, so its of no use saving them.

3. It's time to tackle the coil spring nuts. You better pray you used PB blaster or busted knuckles are gonna be the result. Heat the nut up really well with the butane torch, then use the 1 1/8" wrench on the nut. You will only be able to get it to fit between the coils that low by letting the I beams hang down. It's unlikely that you will be able to get it off with just your strength. This is were the sledge comes in. If it still wont budge and your arms are tired, break out the air chisel and hit the side of the nut till it starts to turn. (The reason I didn't want you starting out with this method, is because you will probably destroy the nut this way) Use your jack and lift up the I beam a bit to compress the coil and finish taking the nut off. Save the dish washer, nut, plastic bushing, and lower dish washer. Twist the coil at the top till it frees from the bucket. Repeat for other side.

4. With the coil gone the last two parts holding it to the truck are the radius arm and the pivot bolt in the drop bracket. Lift the I beam with the jack till there is no pressure on the radius arm bushings. At this time, give the I beam a shove to the rear. Hopefully this will relieve the stress on the nut making it easier to remove. Take your 1 1/8" wrench and tackle that nut. It will tough to get a grip on it so a sledge should help a bit. Don't use the torch! You can use the air hammer on it as well. Once you get it off remove the old bushings and toss. Save the nut.

5. Keep the jack under the I beam. The pivot arm bolt will need two wrenches on each side. You may have to jiggle the I-beam a bit and use the BFH to get the bolt out.

6. This is where a second pair of hands will come in handy. These arms a lighter than the 4wd ttb but they are still heavy. Using the jack as the pivot point, knock the arm out of the drop bracket. Twist the arm down and pull it out of the RA cross member. Repeat on other side.

7. Now the last part of the removal is taking out the drivers side drop bracket. The 4wd TTB uses a different mounting point on the engine cross member. The 2wd drop bracket is held in place with 4 hardened rivets. Your best choice is to drill them out. Battery drills won't cut it here. Now take your grinder or cut off tool and remove the heads. Use the air hammer with the round tip to pound them out. Remove the bracket and toss.

You now have a suspension-less front end. Take a break and grab a cold something or other.

Prep Work

Install your new RA bushings on the TTB and your pivot arm bushings in the TTB arm holes. Spray PB on the coil bolts on the TTB. Take a hose to the under carriage of the truck to clean out any dirt and stuff stuck up in there. Makes it easier on the install. Grease both axle half shafts where they connect to each other. Drain the pumpkin. Note any metal shavings or dark fluid.

Install

1. Get the 4 grade 8 bolts and nuts and attach the new 4x4 drop bracket to the INSIDE of the engine cross member. The bracket is curved to fit the cross member and it should line up with 4 holes on the lower part of the member. If the holes seem a little off, you can open them up a bit with your drill. Tighten the bolts down hard. You don't want to have this thing fall apart on the highway. That's why you are using GRADE 8, right?

2. Drag the passenger side of the TTB under the truck. Use the jack to lift it into place. Put the radius arm (with the new bushing) into the RA cross member and rotate the TTB arm into your driver's side drop bracket. Install your bolt for the bracket, but do not bolt in the radius arm. This will allow you a little movement in putting the coils back in and adding the drivers side TTB.

3. Install your coils. It's easier to install with out attaching the coil to the body yet. The order for assembly is: Dish washer (dish side up), plastic bushing, coil, dish washer (dish side down), nut. Don't tighten the nut all the way. Twist the coil onto the coil bucket and then tighten the nut. Install your shock now on that side. Remove your jack for use on the other side.

4. The pumpkin side of the TTB is VERY heavy, so get some help. Install it the same as the passenger side, BUT make sure you slip the axle shaft over the passenger side slip joint, before you pop the TTB arm into the bracket. Install your driver's side coil and shock.

5. To finish reattaching the front suspension, make sure that the jack keeps the RA parallel to the body, so there is no stress on the new bushing. Install the rest of the bushing on the back of the RA and hand tighten the nut. Have a friend push the RA back toward the cross member. This will expose more threads on the arm. Making sure the arm is parallel to the body, continue to hand tighten the nut this way till you can't turn the nut any more. Now tighten the nut to 80 - 100ft-lbs. Repeat for other side.

6. The steering drag-link system is up next. Its a fairly strait forward process, install the 4x4 steering setup the reverse of the way you removed the 2wd setup. Leave the nuts off the tie rod ends. Remember ALL the cotter pins. Don't rotate the steering wheel when checking new setup. In step 9 I will show you how to get a decent alignment till you can get it to the shop.

7. The next step is to get the rotors and hubs installed. I am going to go with the premise that you are going to use manual hubs on an auto hub snout. Remove the auto hub. There is a little half moon clip on the axle. A small flip with a screw driver should pop it out. Don't lose this. Now remove the splined washer (also don't lose), the other washers and finally remove the plastic cam. Now the the last thing to remove is the auto hub locknut. There is a very tiny metal key that slides underneath the auto hub locknut holding it in place. A good tool to get this key out is a dentist's pick. You may struggle with it for a little while, but you have to hold your tongue just right to get the little bugger out. Once its out you should be able to unscrew the lock nut. Give the rotor a sharp pull forward and it should dislodge the front bearing. Pull the rotor off. Flip the rotor over and pop out the metal grease seal and remove the rear bearing. If you plan on reusing the bearings then relube them and install in your new rotor. If not ditch the whole thing and install new bearings and oil seal in your new rotor. Replace everything on the snout in reverse order up to the auto hub lock nut. Now get your baggies you got from 4wheelparts and pull out the lock nut with the little pin and screw it on, pin OUT. It only needs to be finger tight. Any more and the bearing won't do its job. Now add the washer with the holes. It can only go on one way. Make sure that the pin on the lock nut fits in one of those holes. If it doesn't REVERSE the nut to get it to fit. Add the outer lock nut and tighten it down. Install the splined washer and the c-clip. Put your manual hubs on and your done! Well, at least with this part.

8. Install your calipers (new pads, right?) and your sway bar. If your TTB still had the wires for the ABS sensors go ahead and attach them if you want. Now go around and double check all your nuts and bolts and make sure they are tight. Fill the pumpkin with 80w-90 gear lube up to the bottom of the fill hole. 2 quarts should do it.

9. Put your tires on, but don't drop the truck yet. You need a quick and dirty alignment to survive getting to the shop. Take the tie rod end out of the knuckle on the side you are working on. Now take your level and put its narrow side on the sidewall of the front tire. Move the tire left and right till you get it in the center on the horizontal bar on the level. Have a friend tighten or loosen the tie rod end and then drop it back into the knuckle. If you are satisfied, attach the nut and cotter pin. Repeat for the other side.

10. Drop your truck on its new front suspension! Get it to a shop to get it aligned.

(Ignore the steering setup in this pic. I made a mistake and used the 2wd setup. DO NOT DO THIS.)

Stage 1: Complete!

 

[MrQ]

Stage 2: Transmission and Transfer Case

Transmission
The transmission is an important part of this setup. After you have chosen whether you want to go the auto or manual route, you can read these great tutorials on installing or removing either of these transmissions.

Auto - Heavymentill

Hints

Make sure to remove the exhaust first. Unless you have a body lift you will never get the bell housing clear.
Always install the torque converter into the transmission first, not onto the flex plate
If the transmission will not spike correctly, take a piece of wood and wedge it between the radius arm cross member and the engine and leverage the engine up. The tranny should slide in.
Before reinstalling the exhaust double check all your plugs and vacuum lines.
Fill the torque converter with at least a quart of fluid before reinstall to protect the clutches
Remember to fill the transmission up FIRST before starting the car, then add fluid incrementally as you shift into all the gears.

Manual- 94fourdoor

Hints

You will need a new starter if you are converting.

Transfer case
I am going to assume that you have chosen to go with a BW 1354M and have acquired the shifter and various parts for it.

1. Pull up the carpet

 

[MrQ]

Stage 3: Rear Axle (If Needed)

 

[MrQ]

Stage 4: Miscellaneous

 

[Maniak]

7. Now the last part of the removal is taking out the passenger side drop bracket. The 4wd TTB uses a different mounting point on the engine cross member. The 2wd drop bracket is held in place with 4 hardened rivets. Your best choice is to drill them out. Battery drills won't cut it here. Now take your grinder or cut off tool and remove the heads. Use the air hammer with the round tip to pound them out. Remove the bracket and toss.

The text says replace the passenger side bracket, but the picture is showing the driver side bracket that needs to be removed. Or am I just reading it wrong?

~Mark

 

[MrQ]

You are correct it is the drivers side drop bracket. I'll edit that.

 

[nas]

I realize this is a few years old now but, for reference there is a large difference between the sport and 4door 4wd shafts, almost a foot difference. Found this out when I had to prematurely install my 4wd a4ld in my ex after the 2wd took a dump I had gotten all my parts out of a sport at the local pullapart and found out after the 3hour install of the trans that my sport drive shaft was far to short.....and its not fun riding 10 miles down the road on a motorcycle with a driveshaft strapped to the side of it(only running vehicle at the time and roommate was at work, got some real funny looks down the interstate)