I completed a full 4x4 conversion on my 4Runner this past summer. Completed every bit of work myself except for two welds that were needed for the transfer case shifter relocation. I will create a write up here for anyone interested in doing the same, or if anyone is interested exactly what it took!

I wheeled my 2WD 4th gen for a few years with the boys but I never quite got to do everything they were able to do in their 4x4s. I was looking to up the anti and be able to go farther and hopefully break less parts. In my attempts to hang with the big boys, I blew up my diff rendering my daily immobile. I got stuck easier or couldn’t make it up or over certain obstacles. Strangely enough, my Falken Wildpeak AT3Ws helped me get around just fine in 6”+ of snow without 4x4.

Before you are dead set on completing this conversion yourself, know some things. It cost me about $3000 doing 95% of the work myself. It took me 50 hours having almost no assistance and using mainly basic tools and working on the garage floor. It was a major pain in the ass not having the proper tools, a post lift, or a dedicated week to complete it without other responsibilities. Completing this conversion will be much less of a headache if you have any of these: parts truck, two post lift, transmission jack/cradle, good impact driver, a few days off without much interruption, a separate vehicle to drive, another hand or two, etc.

ALSO. This conversion requires you to cut a hole in your transmission tunnel and reseal it. If you are not okay with this, then this mod is not for you!

Certainly appreciate everything you’re saying. Sometimes specialty tools make all the difference.

I also hear what you’re saying on feeling that you’ve maxed out your trucks ability. I’m there right now. Thinking about next moves - winch, bigger tires, rear locker vs upgrading to a 5th gen

I would personally upgrade to an 8.2” from an FJ or 5th gen 4R. Maybe it’ll already have an E-Locker in it. Regear that either way, and then add a locker if it doesn’t already have one. They are much stronger than our crappy 8”s. Ask me how I know. Winch is always helpful not just for yourself, but for others as well.

I would like to preface this by disclosing some additional information. Unfortunate information for me and very good news for anyone with a V8 wanting to complete this conversion. I only found limited information on all various sites even with the hours and hours of researching I completed before doing this conversion. To remove the transmission, I found a diagram walkthrough which covered removing the A750 (5speed) transmission from the V6, not the V8. Well this is essentially the same process between the two engines since they are the same transmission EXCEPT for that when accessing the flywheel/torque converter bolts on the V6 you have to remove the starter (much easier than the V8) while on the V8, you indeed do not have to remove the starter. You only have to remove a cover plate on the bottom of the bell housing. This changed the whole conversion process for the V8 from being exponentially more frustrating than the V6 to being even easier than the V6 to complete. You’re welcome for me being the test dummy and making the mistake instead of you guys! Without having to remove the starter on the V8, it would have cut down from a fifty hour total working tomorrow to possibly 35.

The first thing you need to do for this conversion is to scour the internet to find your parts and price them. I will attach my parts and price list below.

How I even began to think about making my 2Runner 4WD was that my good friend basically totaled his 07 4x4 V8 when his timing belt snapped. Engine was toast. So basically, he started selling off his aftermarket parts. After those specialty parts were removed, all that was left was the basic 4Runner. The drivetrain was fully intact with no damage anywhere except for the engine. I realized I had a parts truck at my disposal and that with being such great friends with the owner, I figured I would probably be able to get some good deals AND I would have access to it 24/7.

From his 4Runner, I pulled the transmission and crossmember, driveshafts, front diff, CVs (as spares), and spindles with 4x4 hubs on them. By using the manual transfer case and non ADD C8 diff, you avoid dealing with electronic actuators AND you have 2WD and 4WD in your V8.

For pricing, I looked online for days finding the lowest prices of each of those parts and sent him the listings. I was able to get away with the transmission and crossmemember for $400, front diff for $300, driveshafts for $300, spindles and hubs for $150, and the old CVs for $100.

The remaining parts on the attached list I found independent of each other. I’m not going to go super in depth on every single part, but four parts do need some clarification. These are the transmission, transfer case, driveshafts, and front diff. When you are searching for these parts, compare mileage vs price. Find a compromise of the two. Lower mileage will fetch higher prices. When searching, look on eBay, LKQ, PickNPull, Car-Part.com, etc.

In regards for the transmission: If you have a 2WD V8, you have the A750E 5speed transmission. When you are looking for transmissions, you need to buy an A750F model transmission. The E dictates 2WD and F dictates 4WD. The 2WD E model will not work because there is no way to mount the transfer case on the back of it. The 4WD F model has a small bell housing on the rear to mount the transfer case onto. And before you ask, you can not simply swap the bell housing of the F model onto the E model, the internals are different. You also have to buy a 4x4 cross member and transmission mount as your 2WD ones are shaped much differently.

Transfer case: When looking for a transfer case, you need to buy a manual J shifting transfer case out of a 5th gen 4Runner equipped with one or the same manual J shifting transfer case out of an AUTOMATIC transmission FJ Cruiser. Just like with the differences in transmissions, you cannot use the manual transfer case out of a manual transmission FJ, the internals do not work with the A750F automatic transmission. A big challenge when finding my transfer case was that on every one of them I found online except for mine, the shifter and boot were not included with the transfer case. I was also unable to find any shifters online. You may be able to find them at a dealership but lord knows how much that would cost.

Driveshafts: Your driveshaft out of your 2WD will not work anymore whatsoever. No modification will change that. The J shift transfer case is shorter front to back than the V8 electronic transfer case. The J shift transfer case has the outputs on both the front and rear of the transfer case pushed towards the front of the vehicle by 1.25”. The driveshafts that come with the V8 transfer case are designed to have just enough compression to remove them from between the flanges. Since the outputs on the transfer case are pushed forward 1.25”, the front OEM driveshaft will no longer be able able to compress enough to remove it from between the flanges without unbolting either the front diff or transfer case. The rear driveshaft is now extended 1.25” which is at the edge of safe operational limits. What you can do to remedy these problems is you can use the original 4x4 driveshafts. The front will be a pain to service but be less hassle up front. The rear OEM 4x4 driveshaft will need a 1.25” driveshaft spacer with nylocks in order to work. OR you can have custom shafts made front and back. This way the shafts are the specific length they need to be in order to remove them easily and not have to run a driveshaft spacer.

Front differential: This has been much of a debate since the original shop that dictated this information stole tens of thousands of dollars from customers, stripped their trucks, and disappeared. Don’t get me wrong, he did good work before he pulled these criminal stunts, but his integrity and trustworthiness on anything is questionable at this point. He specified that you had no other option but to use a V6 ADD front diff. This diff has an actuator that disconnects the diff from the driveshaft internally which prevents backspin from the diff into the transfer case in 2WD. In theory, this is healthier for your transfer case, but takes a lot more work to fit it. The V8 engine oil pan is not designed to fit that actuator under it. In order to fit the V6 ADD front diff, you have to do any two of these three things: notch the oil pan, get new engine mounts, or add engine mount spacers. Any combination of these will add more clearance between the diff and oil pan. I personally mistrust the actuator because it is known for going out, much like the actuators on the electronic transfer cases. The V8 front differential does not have this actuator. There is no clearance issue with the V8 diff. It does not disconnect, so it backspins into your transfer case when in 2WD. Some people worry about this ruining your transfer case, BUT with much consultation with other knowledge and trustworthy people, we have deemed that this is fine to run the V8 diff. The J shift manual transfer case has a chain driven internal oil pump that is driven off the rear output gear. This means that as long as the rear wheels are receiving power, the transfer case is getting sufficient oil cycling. The only thing that you should 100% do is run an extended breather from your transfer case in case the heat expands minimal fluid out of the breather hole. You should have extended breathers on everything anyways, so not a big deal.

Pictures:
1st parts list
2nd V6 ADD diff (top) vs V8 non ADD diff (bottom)
3rd 2WD trans Xmember (top) vs 4WD Xmember (bottom)
4th comparing A750e and A750 F transmissions

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Here are some helpful links I used before starting my conversion. These walkthroughs are for 2nd gen Tacoma’s but the process is pretty similar minus the crossmember differences and shifter relocation.

MysticZ's 2wd to 4wd conversion - Toyota 120 Platforms Forum

2WD to 4WD Conversion, Part 1 - Toyota Cruisers & Trucks Magazine | Land Cruiser, 4Runner, FJ Cruiser, Tacoma, Toyota Trucks

2WD to 4WD Conversion, Part 2 - Toyota Cruisers & Trucks Magazine | Land Cruiser, 4Runner, FJ Cruiser, Tacoma, Toyota Trucks

Alright it’s time for discussing more parts. You can research and make the decision for yourself, but I chose to use cheap ORiellys CV axles. Some people go OEM which are better but cost a lot more. Pickup gear oil from a parts store and ask them which fluid and how much you need for your specific diff and transfer case. Go ahead and pickup a 35mm 1/2” socket. This will be needed to install your CV axle nuts. Get a heater hose that is small enough to fit into your front diff and transfer case fill holes but large enough for the tip of your gear oil bottle to fit into. Probably need three feet of it.

Buy Toyota specific transmission fluid (ask dealer which type you need for the specific transmission), buy Toyota CV axle inner and outer seals or else you’ll cry at a leaking seal or two.

Since I was getting spindles and hubs off the parts truck, I decided to buy the heavy duty spindle gussets from Total Chaos that retain the sway bar mounts (not that I use my swaybar, they’re just beefier). I’m running these hubs that were already on the spindles and will swap them out with Koyos whenever it’s time.

Nobody has really found a shift boot they like in order to seal up the transmission tunnel after sticking the shifter through. Experiment I guess����*♂️
Skinnier is better for it, I know that much.

I ordered a generic leather shift boot for the cosmetic shifter and a 6” 12x1.25 curved shifter extension to push the transfer case shifter away from my transmission shifter.

If you decide to reuse the rear 4WD driveshaft, you will need a 1.25” spacer from 4Crawler. I will come back and edit in the bolt pattern you need later.

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Acquiring parts:

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For this step, it’s not as important on this step, but it is a good habit to disconnect your battery every time you work on something. It is equally important to chock the wheels to avoid the vehicle rolling. Make sure everything is tightened to spec by using a torque wrench. Installed the front diff, CVs, seals, gusseted spindles, 4x4 hubs a week before installing the rest of it. Be cautious and careful when seating your seals and CVs or else you’ll be fighting an axle leak like me. There should be a seal are the diff and a seal at the back of the hub on the spindle. Stick the splined end of the CV through the diff seal and make sure it snaps to make sure it clicks into place. Slide the 4x4 hub around the outer CV splines, bolt everything else together minus putting the wheel on, then tighten up the outer CV with the 35mm nut and socket. Stick the pin through for security. Don’t booger your threads. Put the wheel on. After you have everything together, fill use the heater hose and gear oil to fill the front diff until it overflows from the fill hole. The fill hole is the top hole while the drain is the bottom. They are 10mm hex keys. Clean them really well and lightly hammer around them with a ballpeen before attempting to open either one or else it could easily strip out. Both are on driver side.

Full List of Suspension Torque Specs For the 5th Gen 4Runner

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Toyota 4Runner: Removal - Automatic Transmission Assembly - Service Manual


Use this for dropping your 2WD transmission. Ignore step 13 and do 14, but a little differently. As I mentioned a few posts ago, instead of accessing the flywheel and torque converter bolts via the starter (V6), you’ll be accessing them via a cover plate. This is located at the bottom of the bell housing where the transmission meets the engine. I believe it’s a 10mm or 12mm.

You will need a dedicated transmission jack or a transmission cradle that attaches onto a rolling floor jack. This will support and move your transmission. May want a hand to steady it while it’s removed/ moved out from under the vehicle/jacked up into place.

AN IMPORTANT NOTE: You will need to pull off the shift position sensor from both transmissions. It is located on the passenger side and is kind of in the shape of a triangle. Swap your 2WD sensor onto the 4WD transmission. This is how it will work with your ECU system. They have the exact same pin layout besides the 4WD having one extra pin for center diff lock. Even with this similarity, the plugs are completely different. Unscrew the nut then gently slide/pry the sensor off the stud using a flathead or etc. By doing this, you get to bypass needing the 4WD ECU. In other words, your 4Runner won’t even know that it is 4WD.

The link below will walk you through installing your transmission.

Toyota 4Runner: Installation - Automatic Transmission Assembly - Service Manual


When you seat your torque converter, you HAVE to make sure it clicks into place three times. There are different three different levels of spline gears inside the transmission so you have to make sure the torque converter goes all the way in and seats on each one. You may have to wiggle and play with it to have it seat correctly. It took me thirty minutes to finally get the last click. Once you get the third click, check the mounting depth front the bell housing. Compare it to the protrusion of the flywheel mounting surface from the block. I’d you do not mount the torque converter all the way in and try to put the transmission on, it’ll wreck your transmission that you just spent so much time swapping. Look up some videos and info on seating a torque converter!

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Make sure shifter on transfer case is in top left (2Hi) position then remove shifter via four mourning bolts. If you are using an OEM 4WD front driveshaft, attach it to the front transfer case output flange. Raise the transfer case up to the back of the transmission with a floor jack and/or you and a friend and get the driveshaft lined up with the input flange of the front diff. Gently stab the transfer case into the transmission. Wiggle it to get the splines to line up and the bolt holes to line up. Get a few bolts started to support the weight, then work your way around somewhat in a star pattern to secure it onto the transmission. I believe they are 12mm and/or 14mm but don’t take my word for it. I think there are ten bolts. But again don’t take my word for it. Your front facing output flange should be on the driver side.

You will need to remove all of the interior trim on your transmission tunnel in order to make your hole for the shifter to come up through. You will also need to remove the AC/heat vent that runs from underneath the HVAC controls to the rear vents. Use Gorilla tape to block it off under the HVAC control area. Unbolt everything that is secured to the transmission tunnel and move it to the side as much as possible. This includes your transmission shifter assembly. The hole you will be cutting will be about as big as your hand. Use my pictures as a reference. Remove the cubby and two plastic dividers from the top piece of trim in order for the shifter to come up through.

Cleanly cut the shifter 1/2” above where the domed retaining washer would sit. You will need to weld in a piece of bar stock extending towards the back left corner close to 45 degree angle. This will reposition your shifter to come up through that cubby hole next to the transmission shifter. You may have to weld it ten times before you get it where you want it to be. You need it to clear the full shift range without hitting anything with all of the trim set in place. In order to shift the transfer case, the transmission needs to be in neutral. How you can get into neutral with no key in the ignition is to pop off the little square tab on the top left corner of the transmission shifter, push that button down underneath, and while holding it down, put your foot on the brake and shift into neutral, then foot off the brake. Your truck should still have emergency brakes on. Once you get the shifter how you like it, seal up the hole with a sheet of aluminum, silicone, and self tapping screws. Then screw the rubber shift boot to that to keep water from coming inside.

Finally, secure your cosmetic shift boot to the trim by drilling little bitty holes along the lip underneath and punching holes in your cosmetic boot, then zip thing them together.

Install your custom length rear driveshaft or the OEM 4WD rear driveshaft with 1.25” spacer.

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Check your torque specs on all bolts.

https://www.purefjcruiser.com/docs/2...ion/003010.pdf

Fill your transmission and transfer case with appropriate fluids and amounts. Run the transmission fluid level check procedure you can find on the forum.

Since your 4Runner doesn’t know that it is 4WD, you won’t have to connect the transfer case wires to anything, as your 4Runner doesn’t have the correct wiring or plugs to connect with. Your dash doesn’t even have the appropriate indicator lights for 4x4, 4Lo, etc. You will be fine driving without them, but if you do want some dash indicators, message me and I will hook you up with a custom harness.

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Amazing write up, thank you so much for posting this. When I first got my 4Runner I did research to figure out the process for converting 2WD to 4WD. For part of my research I compiled a parts list for everything I thought I needed. I just went back and compared said list with your parts lists and was surprised at how many items I had missing haha.

I never did the swap because I couldn’t justify the price/work to have 4wd when I don’t really need it. However, if my transmission ever poops out on me I’ve told myself I will do the whole swap at that point. Saving this in case that day ever comes. Im sure if I had a donor vehicle with all the parts I’d follow the same path you did. What would you say was the hardest part of the build? Did you do it all with both vehicles on jack stands? Impressive.

Thanks again for posting all the lessons learned.

Now add a supercharger.


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Great write-up. Thanks for posting it here and not just on one of the Facebook groups (where I saw you post the link).

Here's this post saved in the Internet Archive for posterity/incase something happens to this site: https://web.archive.org/web/20220110...onversion.html