3rd Gen Factory E-locker Retrofit in a 4th Gen

This is a project I've been wanting to start on for so long. To keep things short, the e-locker 3rd member from a 3rd gen 4Runner will work in a 4th gen. They're both 8" diffs, and Toyota has kept the design for the 8" diffs pretty standard over the years so that's why it works. There's just a handful of things you need to do to get everything working in your 4th gen.

Step 1: Find an e-locker diff in a junkyard
This is the cheapest way to get a factory Toyota e-locker. You'll have to be patient, but I got an entire rear axle from a 3rd gen from the junkyard for $200. Pulling the entire axle is easiest to do at the junkyard, so just sell of the shafts and housing afterwards if you don't need them.

Step 2: Purchase the 12voltguy wiring harness
This wiring harness is QUALITY made. Comes with everything needed from the diff to switch to make the locker work. The harness has a nice braided sheath that protects the wires, and it comes with the breather tube for the actuator included. About $135, but WELL worth it for the quality and ease of install.

Shopping Cart

Step 3: Add material to axle housing
The e-locker diff stud pattern is slightly different for the 4 studs that hold the actuator motor in place. To drill and tap these studs, you have to add material to your axle housing. I have not gotten to this part yet, but have a local shop that can weld the added material on for cheap.

Step 4: Drill and tap actuator stud holes
Now, you need to drill and tap the 4 holes that service the actuator motor. I plan on using a cheap e-locker gasket to line up the holes, but then use RTV later to actually seal the diff. I'd also recommend on investing in a guard for the actuator if you plan to do any serious wheeling. All of this stuff you can get from low range offroad:

Toyota Electric E Locker Gasket, Studs, Hardware

Toyota Electric E Locker Motor Guard - Low Range Off-Road

Tap and Drill Bit for Modification of Axle Housing

Step 5: MAKE SURE GEAR RATIOS MATCH
This is something I neglected to cover when I initially made this thread. Thanks to [MENTION=68704]superman3043[/MENTION] for bringing it to my attention. For 3rd gen 4Runners, most e-locker differentials came with a 4.30 gear ratio from the factory. So, I plan to order a built front differential from East Coast Gear Supply with 4.30 gears as well so that the ratios match in both diffs.

I won't be installing both diffs at the same time, so I'll just be running around in 2WD until I get the built front diff from ECGS and have time to put that in.

Step 6: Install diffs, wire, and wheel!


So far I've just gotten the wiring harness and made sure the locker still works. I got really lucky with the diff I pulled. All the bearings were mint, the gears were in great shape, and so was the locker and actuator motor. Looked like it had never been pulled from the axle I got it from, so it was still setup like factory Toyota.


As I make progress on the install I'll be posting updates on this thread. Should have the install complete by the end of the summer.

In the meantime, happy wheeling!



P.S. Here's a link to a video of the locker engaging and disengaging in case you were wondering what it looked like. Thought it was pretty cool to see:

Untitled | Ryan King | Flickr

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Photos would be great! Im more of a visual learner and this seems like a sweet mod.

Hey man! I'm going through my second round of this mod currently.

Bought another locker and harness just because I was too lazy to troubleshoot what was going on with mine. Hoping everything would just be plug and play... Tried it out this weekend and it didn't work. Ugh. So now I gotta wait until I got time to fool with it to figure out what is going on.

I think you got it mostly covered. Just make sure your gear ratios match. I didn't really understand the bit you have on Step #3 about adding material though.

Good luck with the retrofit! Any help I can offer, just LMK.

I have this mod. Unfortunately everyone seems to have the same problem, that is the motor gets stuck underwater and seems to jam and then people complain. Also, when the motor gets bogged down it draws more current and either blows a fuse or smokes the cabling.

I solved this common issue by doing 2 things:

1: took the actuator apart and removed (ground off) material from the raised block that stops the motor from turning around infinitely. It also happens that this is where it jams, the raised block hits the housing and gets stuck.

2: completely ditched any and all wiring methods that most 4wd sites seem to keep reposting and used 2 40A relays connected in 'reversing polarity' mode, this is the same as what is used for power windows.

The first item stops the motor from jamming or failing EVER because it simply can't jam or fail. The second item provides 4x the current to the motor, giving it more power when you need it. I was tired of the motor failing to engage because there was the slightest bit of tension on the axles. Most of this has to do with the wire gauge and length, you simply can't get 40A of current through an 18awg cable. I used 14awg OFC 4 conductor cabling for this purpose, fake chinese wire was used on the original install, which obviously failed.

I want the actuator to engage NOW and I don't care what it's opinion is on the matter. Waiting 10 minutes for it to lazily decide that maybe its time to consider engaging is not an option.

Why not just get a Eaton E locker?
No mod to housing,no rebuild kit, if you use a older toyota e locker you won't be able to re use stock R&P from 4th gen,they're different,add a new pinion flange to fit the new 30spl R&P.
I did what you're doing thinking I was saving money but in the end it cost me more than just buying a Eaton and re using all 4th gen parts,just the down time alone makes using all 4th gen parts worth it.

Ida4runner said:

Why not just get a Eaton E locker?
No mod to housing,no rebuild kit, if you use a older toyota e locker you won't be able to re use stock R&P from 4th gen,they're different,add a new pinion flange to fit the new 30spl R&P.
I did what you're doing thinking I was saving money but in the end it cost me more than just buying a Eaton and re using all 4th gen parts,just the down time alone makes using all 4th gen parts worth it.

Click to expand...

Hey man...

That is all wrong. I have the original 4th gen ring and pinion installed onto my 3rd gen elocker right now. There are no problems with the installation and everything works normally without any modifications of any type. The 8" ring and pinion from all years of all toyotas (even cars) work on all 8" trucks except for the 3rd gen factory 4.88 housing. The problem is the companion flange (depending on the year).. since the 8" trucks only have 2 possible patterns, you just need to either reuse the 3rd gen elocker flange or get a triple drilled flange. Problem solved.

FYI - the 3rd gen elocker flange pattern mates perfectly with the 4th gen driveshaft. No issues.

duffdog said:

Hey man...

That is all wrong. I have the original 4th gen ring and pinion installed onto my 3rd gen elocker right now. There are no problems with the installation and everything works normally without any modifications of any type. The 8" ring and pinion from all years of all toyotas (even cars) work on all 8" trucks except for the 3rd gen factory 4.88 housing. The problem is the companion flange (depending on the year).. since the 8" trucks only have 2 possible patterns, you just need to either reuse the 3rd gen elocker flange or get a triple drilled flange. Problem solved.

FYI - the 3rd gen elocker flange pattern mates perfectly with the 4th gen driveshaft. No issues.

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Cool,glad to hear that,thanks for the info.
I tried taking the R&P from a 4cyl and putting them in a E locker and they were different which required new gears and flange,probably due to my 5.29 gears, not stock like yours.
If I was doing it again I'd still do a Eaton as the drill/tap, housing notch,adding material was a PIA.

royal T4R said:

Photos would be great! Im more of a visual learner and this seems like a sweet mod.

Click to expand...

Sorry about the lack of pictures! I'm not very far into the install process yet, so I don't have any pics of these actual steps quite yet. For the links I included you can see pictures of the harness I bought, the actuator guard, e-locker gasket, and the drill bit and tap needed. Also, I included a link to a video of my locker engaging and disengaging in the first post. I plan to add many more pictures once it's complete. Just wanting on parts to come in!

superman3043 said:

Hey man! I'm going through my second round of this mod currently.

Bought another locker and harness just because I was too lazy to troubleshoot what was going on with mine. Hoping everything would just be plug and play... Tried it out this weekend and it didn't work. Ugh. So now I gotta wait until I got time to fool with it to figure out what is going on.

I think you got it mostly covered. Just make sure your gear ratios match. I didn't really understand the bit you have on Step #3 about adding material though.

Good luck with the retrofit! Any help I can offer, just LMK.

Click to expand...

Thanks man! You're right, I completely forgot to mention gears. I'm gonna update the first post to include this info, but the diff I got came with 4.30 gears, so I plan to order a front diff from ECGS with 4.30 as well. That way, i'll come out of this with a locker and gears for a decent price.

As for the adding material part, I'm alittle unsure on it too. I have a buddy that has a Toyota buggy and knows just about everything there is to know about Toyota's, and he was saying that the e-locker stud locations are kinda halfway on the housing where it has differing material thickness. I'll have to ask him about it again but that's all I can remember for now.

Sorry to hear you're having so many problems getting yours to work! Luckily the one I got is pristine. The gears are in great shape, the bearings are all perfect. The actuator motor engages strongly and has no trouble engaging and disengaging. You could tell by how well sealed the diff was in the housing that it had never been pulled before, so it was likely still setup like factory Toyota spec. & then it also seemed that the locker itself had been used minimally, if at all.

Initial Post Update

I updated the first post to include my plans for gearing. Thanks to [MENTION=68704]superman3043[/MENTION] for bringing this up!

I'm currently waiting on the e-locker gasket, actuator motor guard, and the drill bit and tap to be delivered to me. Hopefully those will get to me sometime next week. Then once they come in, the plan is to tear everything apart and get the locker slapped in ASAP!!

I'm glad people are having a discussion about this mod. I haven't gotten much more done on mine. Need to pull the actuator and test it. I bought it used from ECGS and they supposedly test them all.

But while I did have a little bit of time, I decided to test my old one. I was supposed to ship it back to ECGS and they were going to give me a little money back because I thought it was still good. Just needed to repack the connector because two of the leads were yanked out (long story). I never got around to sending it though. I tried to test it and it didn't run. Well, I was surprised to see that it was absolutely disgusting in there after taking it apart. Looked like dirt, mud, and rust. Nothing like the last time I was in there 6 or so years ago. No way this thing would work. Not 100% sure how it got like this, but what I did notice while I was under the truck was that I did that mod where you tee the locker breather into the extended diff breather at some point. This could be the cause or at least part of it. I cleaned it up and left it to dry, but not sure if I can get it working again. The mechanical bits like the sprockets, shaft, clock spring, housing, etc. all cleaned up fine, but the motor and worm gear look pretty spent. We'll see. Anyway, I hope to get this wrapped up sometime after next week, so that I can move on to the next thing.

Had to do it all over again, I don't think I would have gone the Toyota e-locker retrofit route. It's been nothing but a PITA for me.

superman3043 said:

I'm glad people are having a discussion about this mod. I haven't gotten much more done on mine. Need to pull the actuator and test it. I bought it used from ECGS and they supposedly test them all.

But while I did have a little bit of time, I decided to test my old one. I was supposed to ship it back to ECGS and they were going to give me a little money back because I thought it was still good. Just needed to repack the connector because two of the leads were yanked out (long story). I never got around to sending it though. I tried to test it and it didn't run. Well, I was surprised to see that it was absolutely disgusting in there after taking it apart. Looked like dirt, mud, and rust. Nothing like the last time I was in there 6 or so years ago. No way this thing would work. Not 100% sure how it got like this, but what I did notice while I was under the truck was that I did that mod where you tee the locker breather into the extended diff breather at some point. This could be the cause or at least part of it. I cleaned it up and left it to dry, but not sure if I can get it working again. The mechanical bits like the sprockets, shaft, clock spring, housing, etc. all cleaned up fine, but the motor and worm gear look pretty spent. We'll see. Anyway, I hope to get this wrapped up sometime after next week, so that I can move on to the next thing.

Had to do it all over again, I don't think I would have gone the Toyota e-locker retrofit route. It's been nothing but a PITA for me.

Click to expand...

I feel like the e-locker retrofit is a very hit or miss job. You either get lucky or it turns into a huge ordeal.

Also, I got some answers for you about the adding material part. I talked to my buddy, and he said that for our non-elocker 4th gen axle housings, the area of the housing where the studs are mounted is thicker than the rest of the housing. When you do the elocker retrofit, the 2 long studs for the actuator are positioned in the thinner portion of the housing. People have just tapped the new hole locations and been done with it, but it's probably a better idea to go ahead and add material to make it close to the same thickness as the other stud locations. I'm hoping I'll be able to explain that better once I actually do the install and can take some pictures.

You also have to cut a notch out of the housing to make room for the locker collar that slides in and out of the diff. It doesn't seem like it at first glance, but the elocker diff is alot bigger than a standard diff, that actuator motor sticks out pretty far.

ryanking61 said:

I feel like the e-locker retrofit is a very hit or miss job. You either get lucky or it turns into a huge ordeal.

Also, I got some answers for you about the adding material part. I talked to my buddy, and he said that for our non-elocker 4th gen axle housings, the area of the housing where the studs are mounted is thicker than the rest of the housing. When you do the elocker retrofit, the 2 long studs for the actuator are positioned in the thinner portion of the housing. People have just tapped the new hole locations and been done with it, but it's probably a better idea to go ahead and add material to make it close to the same thickness as the other stud locations. I'm hoping I'll be able to explain that better once I actually do the install and can take some pictures.

You also have to cut a notch out of the housing to make room for the locker collar that slides in and out of the diff. It doesn't seem like it at first glance, but the elocker diff is alot bigger than a standard diff, that actuator motor sticks out pretty far.

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Hmm.. Makes sense I guess, but I don't remember encountering anything like a thin area. Been so long ago though. but yes, you definitely need a notch to clear the fork. One thing to definitely look out for is high spots on the axle housing mating face. First time I put the diff back in, it didn't seal that great and had to pull it, knock down the mating faces a tad and close it back up. Another day spent fooling with this mod.

I hate to think back on the hours and money I've spent messing with this thing, especially for the return on investment, as I've never actually needed it wheeling. It started out good, as I got the elocker diff for free. I learned a lot from the project including how to rebuild a diff, but when I think back, it's truly been a lot of cost, time, and effort spent on a nick knack that gets next to zero use. I've literally gotten more ROI on my winch than the locker. Not from recovering myself, but recovering others and using it to do work. And that's an equipment investment that I've always felt was a luxury, "nice to have" item. In the end, all of the money I've poured into this thing gets put to very little use these days. But I think I'd do it all over again, because I learned a lot. Some things I might do differently knowing what I know.

superman3043 said:

Hmm.. Makes sense I guess, but I don't remember encountering anything like a thin area. Been so long ago though. but yes, you definitely need a notch to clear the fork. One thing to definitely look out for is high spots on the axle housing mating face. First time I put the diff back in, it didn't seal that great and had to pull it, knock down the mating faces a tad and close it back up. Another day spent fooling with this mod.

I hate to think back on the hours and money I've spent messing with this thing, especially for the return on investment, as I've never actually needed it wheeling. It started out good, as I got the elocker diff for free. I learned a lot from the project including how to rebuild a diff, but when I think back, it's truly been a lot of cost, time, and effort spent on a nick knack that gets next to zero use. I've literally gotten more ROI on my winch than the locker. Not from recovering myself, but recovering others and using it to do work. And that's an equipment investment that I've always felt was a luxury, "nice to have" item. In the end, all of the money I've poured into this thing gets put to very little use these days. But I think I'd do it all over again, because I learned a lot. Some things I might do differently knowing what I know.

Click to expand...

Hopefully mine will go somewhat smoothly....if it doesn't work I guess I'll go a different route and you can say "I told you so!"

ryanking61 said:

Hopefully mine will go somewhat smoothly....if it doesn't work I guess I'll go a different route and you can say "I told you so!"

Click to expand...

I hope it goes smooth and works perfectly for you as well my man. I'm definitely not trying to discourage you from doing it. I say go for it. Just sharing my experience and letting you know I'm here if you have questions or if there is something I can help with. Good luck!

It's done!

Hey guys! It's been awhile since I updated this but the E-locker retrofit is DONE! Sadly, I didn't get around to doing it this summer, and with working this semester, I did not have time to do it myself. So instead, I worked it out where I dropped it off at a local shop, Southeast Overland. They did a killer job, and the new owners are the best people. They got me taken care of and did it for a great price!

So, before I picture dump, here are some notes:
They did the E-locker retrofit per a write-up I found on a different forum (I don't remember right now, but I'll summarize). To make the E-locker fit, you have to use a plasma cutter and cut a notch out of the axle housing to make room for the fork to slide over when the locker is disengaged. Additionally, 4 new stud locations must be drilled and tapped for the actuator studs to work.

MAJOR IMPORTANT NOTE
If you have a 4th gen and are going to install a 3rd gen 4Runner E-locker 3rd member, you NEED a new pinion flange. The 3rd gen differential pinion flange has 27 splines and a 60mm by 60mm flange bolt pattern. 4th gens (at least mine) have a 29 spline pinion flange with a 66mm by 66mm bolt pattern. The difference in the flange sizes is too different to just drill out new holes, so you absolutely have to get a new pinion flange for this to work. This was a catch that Southeast Overland solved quickly, and I thank them for it. The pinion flange I got is a nitro gear flange that is triple drilled.

Here's a link to the flange: YOKT35040-MULTI

Along with the E-locker, I had them beat my lower link frame mounts back out since mine were pretty beat, and I had them weld on Outpost Offroad Lower Link Guards. I also had them weld on some RuffStuff universal tube reinforcements and weld on the eimkeith Panhard Correction Kit. Additionally, I had them install a Low-Range Offroad Actuator Motor Guard to protect the actuator.

Links to those parts:
FJ Cruiser/4Runner/GX470 Outpost Off Road Link Guards
Universal Tube Reinforcement (Single) - RuffStuff Specialties
PCK (Panhard Correction Kits) – eimkeith.com
Toyota Electric E Locker Motor Guard - Low Range Off-Road

Finally, I used the 12voltguy E-locker wiring harness to wire it up. It's an amazing wiring harness that is well worth the money. Southeast Overland slightly changed the wiring for the harness though. If you install the harness how it comes, you would turn the switch to the "on" position and the backlight for the rocker switch would turn on. HOWEVER, this would not mean that the locker was actually engaged, you would have to listen for the clunk of the locker actually engaging. So, to avoid confusion of when the locker is engaged, they changed the wiring so that the rocker switch backlight ONLY comes on when the locker engages. This means when I turn the rocker switch to the on position, the light remains off until the locker physically engages. Only then does the backlight turn on. This makes it far easier to know if your locker is actually engaged or disengaged.

Okay enough talking, picture time!
















It's sad I didn't get to do it myself, but I'm so thrilled to have it all installed nonetheless.

To make things even better, my built front diff from ECGS with matching 4.30 gears shipped 2.5 weeks sooner than expected, and was delivered to me the day after I got the 4Runner back from the locker work. So naturally, yesterday I went ahead and installed the front diff too Time to wheel!

Nice man! Glad to hear you got it squared away. Got mine finished up again a while back and my eimkieth PCK done last weekend. My 12 Volt Guy harness functioned like it should out the box though. Light illuminates when in the locked position. Wierd that you had to change yours.

ryanking61 said:

Hey guys! It's been awhile since I updated this but the E-locker retrofit is DONE!. . .

Okay enough talking, picture time!

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Nerd question; any idea what paint they used on the frame and axle? Looks almost OEM from here...

eimkeith said:

Nerd question; any idea what paint they used on the frame and axle? Looks almost OEM from here...

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Sorry for such a delayed response, but I have no idea what paint they used. It looked good at first but now it looks like the factory worn paint again.