2wd to 4wd Conversion

[grihn]

Hello,

I have a '91 Explorer 2wd that I'm looking to convert to 4wd. I don't plan on doing any major off-road playing with this, I mainly want to do it for snow, and the only thing I don't like about my current Explorer is that it's 2wd.

The reason I want to convert rather than just buy a 4x4 and use that is I recently picked up my '91 in very good condition, and it only has 66k on it...this vehicle is my daily driver, and I don't really want to tag/insure a vehicle to use a few months out of the year. My plan so far is to buy a 4x4 on craigslist and just swap the necessary parts and then scrap it.

My questions are as follows.

1) If someone could provide me with the exact parts (or a link) that I'll need to swap I'd appreciate it...I did a quick search but didn't find everything.

2) I really hope to use my existing transmission, because of the low miles. It's an auto tranny...can I put the transfer case from a 4x4 on this transmission, or are the transmissions themselves actually different? If the transmissions are different and I have to swap them, I may buy a remanufactured one because I don't really want to put a transmission in with 100k+ and be having issues with it...if I have to get a remanufactured one, can someone link a good place to buy one? I've seen 'em on ebay, and may just get one of those if I have to unless you think there's somewhere better/cheaper.

3) How do I make sure the gear ratio's are the same in the differentials? I'm pretty sure I have 3.73, but how can I check to be sure (preferably without opening the differential and counting!) and how do I verify the one I purchase is the same?

4) I think I know the answer, but I should be able to purchase any first gen (91-94) Explorer without any of the necessary parts being different, and when I do the swap everything should pretty much line right up, correct?

5) I recently replaced the brakes in my Explorer...are the 2wd and 4wd front break parts the same? I think they would be, but on ebay they have different auctions for 4wd and 2wd, but....it's ebay so I wasn't sure if that meant anything.

6) Last question, when I do this I am probably going to put a manual hub conversion in...how does this work with push button 4x4? I would assume you just lock in hubs, then engage the 4wd and everything else is normal (as far as switching to low 4, etc...).

Thank you for your time.

 

[shooterdude199]

Well what you can do is look into getting a 4x4 bell housing and replace the tail shaft on your transmission also when you get a manual transfer case it will be much easier to do because there is almost no wiring involved compared to if you wanted the auto t case. With gear ratios go look on your spoof jamb and you will find an axle code... for example 42 is the axle code that has 410 open diff. Someone can link you that page on explorer4x4.com. I also wouldn't be sure of the brakes id imagine no because of there being an actual axle and not just a spindle. Hope everything goes well

 

[tweakedlogic]

I think it would be much easier if you watch craigslist (or ask) for a blown up/ broken Ranger or Ex. You can find them for about $500 sometimes less. That way you have everything there and a map for how to install it. Plus you may get many other useful parts.
Optionally, you can install a solid front axle and divorced transfer case. but it will cost you way more than $500.

 

[Derek Greenwood]

I just did the 2wd to 4wd conversion

I just finished my 2wd to 4wd conversion on my 94 Explorer Sport. It is not a weekend job! First of all you would need to remove your automatic and take it apart and put on a new rear tail shaft and tail shaft housing. I was having my transmission rebuilt so I had them make the swap. I wanted a manual transfer case but for the life of me couldn't find an explorer one so I got one from a bronco II. The linkage was a little short so I had to weld about an inch onto the manual linkage. I replaced my rearend and upgraded it to a newer disk brake one for two reasons. First of all I tow a popup trailer and I wanted better brakes. Secondly I had 3.08 gears and they sucked. So I went to 3.73's. Then I bought a front clip from a guy who was parting out a 4wd explorer. Unfortunatly it had 4.55 gears so then I went to a u-pull salvage yard and got a 3.73 diff. You have to take the 2wd passenger side ttb mount out and replace it with the 4wd one. You don't have ABS so it doesn't really matter what year front assembly you get. The brake pads and calipers from you 2wd can be reused as can the shocks. You need to switch over all the steering except for the pitman arm.

There are a lot of small details like cutting out a hole for the manual shifter for the transfer case and then finding a rubber boot to seal the hole.

Cutting the rivets for the TTB bracket from the 2wd and the 4wd chassis and then bolting in the 4wd bracket into your 2wd chassis.

I did the c-clip eliminator modification while everything was apart.

I also cleaned and painted everything. I replaced all the bearings, seals and ujoints.

Oh, if you use a bronco II transfer case you must also use the bronco II front drive shaft as it attaches differently to the transfer case. I had to have mine shorted 1 1/2 inches to fit as the diff on the explorer is longer than the bronco II one.

You also have to either switch the drivers side bump stop or cut down the 2wd one to match the hight of the 4wd one.

I replaced all the front bushings with poly ones as well as the rubber ones were long dead.

When you put in the transfer case you will also have to change out the rear drive shaft to a 4wd one. Also the spedo cable is too short so you have to change that too.

All in all it took me about 9 months to transform my explorer. But during that time I also put in newer power seats. Put on new heads, radiator, waterpump,all engine electical parts, injectors, ignition, all ac parts, heater and so on.

With my tires and wheels and everything else I have almost 5000 in my truck. I didn't mind spending that much as most everything is new or rebuilg

 

[tweakedlogic]

Good post Derek.

As you can tell from Derek's post, it will be far easier to have both vehicles side by side to do the swap.

 

[grihn]

Thanks Derek, that's very helpful.

I have been looking on craigslist...I agree that I should just get a parts truck. Is there a reason that you wanted a manual transfer case rather than the auto? Are they more durable? That doesn't sound like too much extra work (given the amount that needs to be done) if it's better.

Thanks for all the help! I have a lot to consider.

 

[FIND]

manual transfercase means you don't have to add all the wiring, switches and computers for the 4wd, which for most people would be the hardest part of the swap. With a manual transfercase, all you need is the 4wd trans, transfercase, engine crossmember, driveshafts and the front end components. No changes to wiring.

Having the manual transfercase basically changes a swap from several weekends into something that you can finish in 1 weekend.

A more minor concern is that you don't have to worry about shift motors going bad, which plague the electronic transfercases.

 

[Derek Greenwood]

I did the conversion in stages

I did not get a parts car because I couldn't get one with a disk brake rearend and a manual transfer case. I didn't want an electric transfer case cause I live in Florida and will only only once in a while put it in 4wd. I wanted it to work when I needed it and with all of the humidity here I was afraid when I really needed it it wouldn't work.

So I bought a Bronco II transfer case and a Bronco II transmission rear tail shaft and tail shaft housing. Then I bought a rear end with 3.73 gears. Then I bought a front frame clip. The guy I bought it from had removed the body and had cut the frame off just the suspension.

First I had the transmission rebuilt and had them install the new tail shaft and tail housing. When they put the transmission back in the also put in the transfer case. I had gone to the junk yard and had purshased a correct length rear drive shaft. So when I got it back from the transmission shop I at least had the case in. Then I went back to the junk yard and got the proper length spedo cable. The spedo gear was set for 3.73 gears so I just left that in until I took out my 3.08 and install the 3.73 rearend.

Next I rebuilt and then installed the 2nd gen disk brake rearend. It took longer to rebuild it then to install it.

Then I did the front end which took quite a while because I rebuilt it and painted it and so on. Do the C-clip eliminator. Its a lot of work to pull the diff if you break and axle or need to replace a u-joint.

Make sure you switch to the 4wd front springs. They are taller and stiffer than my 2wd Explorer Sport springs were. My Sport also has 3 leafs in the back and the bigger 2nd gen rear swaybar. This is a nice road package and worked just fine in the Turkey something OHV park in Kentucky that I went to 3 weeks ago.

If you need to keep your car on the road you have to do this conversion in stages like I layed out above.

I got really good prices on stuff and it still cost me between 2500 and 3000. Of course 1500 of that was the transmission rebuild.

By the way, when the transmission is out it is possible to replace the oil pan gasket by unbolting the engine mounts and lifting the engine. Also make sure you put in a new rear main oil seal.

I love my Sport and plan to keep it for a long time. It is completely rust free so why not.