Axle swap, Lockers, Gear Info for my new build

[SunPilot]

Hi fellows, and ladies. I just purchased a 2007 Sport two days ago. I will be setting it up for overlanding. I intend to use a moderate lift, maybe 2.5 to 3" max. Probably tires in the 33" range max. I am reading all day, every day, forums and posts to get as much info as possible. Sometimes I can't find the answers I need through searches, and this is one of those times.
My question today is about rear lockers. I am coming from a Jeep Rubicon, and I know the advantages of having at least one locker on the trail. My intention is to use a rear locker only, as I will have a winch in front. During my research I have learned that ARB is probably the way to go. I have also learned that our 4th gen 4Runners use Toyota 8" axle, a very old setup. The newer (5th gen) Runners have a newer 8.2" rear. from what I have learned it is a slightly beefier setup (larger bearings and gears). Some models have the ELocker but the 3rd members are not interchangeable. My question is simple... could I just swap in a complete 5th gen rear Elocker axle to my 4th gen Runner? I'm thinking it would give me a slightly beefier axle and gears, the locker I need, and probably a lot cheaper than getting an ARB installed and re-gearing. What are your thoughts? Has anyone gone this route?

 

[Tooltime19]

I too have considered looking for a complete rear end housing with the OEM locker so all I would have to do is drop it in and do some wiring. My other thought was to install a manual locker like the Lock Right or a Detroit Locker. I would prefer a locker that I can switch on or off at my discretion.

 

[Inv4drZm]

I'm not sure anyone has had any problems with the 8" diff when rebuilt with a solid pinion spacer. It might be old but is sure a bulletproof setup from what I've been told. Do you have the V8? Mine laughs at it's 33's. I wouldn't regear until I had 35's even then I might keep it stock unless I went to full lockers or something. Also, I haven't seen anybody swap in a 5th gen axle on the forums. I'm doubting it would just bolt on with all the shock mounts and linkage mounts in the exact same place.

 

[SunPilot]

I too have considered looking for a complete rear end housing with the OEM locker so all I would have to do is drop it in and do some wiring. My other thought was to install a manual locker like the Lock Right or a Detroit Locker. I would prefer a locker that I can switch on or off at my discretion.

I like to be in control of the lockers also. ARB or ELockers seem to be the best options.

Yep, it seems a great deal less trouble to swap a complete axle and throw in a switch and relay.

 

[SunPilot]

I'm not sure anyone has had any problems with the 8" diff when rebuilt with a solid pinion spacer. It might be old but is sure a bulletproof setup from what I've been told. Do you have the V8? Mine laughs at it's 33's. I wouldn't regear until I had 35's even then I might keep it stock unless I went to full lockers or something. Also, I haven't seen anybody swap in a 5th gen axle on the forums. I'm doubting it would just bolt on with all the shock mounts and linkage mounts in the exact same place.

I've read a few posts about axle failure, especially heavily laden rear ends. I believe that is why Toyota beefed up the rear axle on the 2010+ models...they are heavier than 4th gen. Since mine will be an overland rig, it will be tasked with carrying a lot of gear, plus the bumpers, winch, and roof top tent! A little more beef can't hurt. Not to mention that the 8.2" gears are stronger also, especially if you were to go to a lower gear set. Lower gearing means a smaller pinion, which is a weaker pinion, and less tooth contact with the ring gear. I guess that's why Ford 9" is so bullet proof!

Yes...I have the v-8. Happy to hear the engine is up to the task...33's are the biggest I will be going, probably. Just got it on Tuesday. Loving it so far in stock condition, but anxious to start the mods. Suspension first!!!

I haven't seen a swap either, thus the reason for this thread. Maybe I'll be one of the first, and if I do it, I will certainly document the hell out of it. From what my research shows so far, the 5th gen and 4th gen share identical chassis, etc. That's good news so far. I'm going to try to find a 5th gen to take some measurements to compare with my 4th gen. The saddest part of this is, I HAD a 5th gen trail edition, as you can see in my avatar. I traded it two years ago on a Caddy SRX. Then bought a Jeep Rubicon for off-roading. Sold the Rubi because I needed a larger vehicle for over-landing, thus the new '07 Runner.

 

[duffdog]

I've read a few posts about axle failure, especially heavily laden rear ends. I believe that is why Toyota beefed up the rear axle on the 2010+ models...they are heavier than 4th gen. Since mine will be an overland rig, it will be tasked with carrying a lot of gear, plus the bumpers, winch, and roof top tent! A little more beef can't hurt. Not to mention that the 8.2" gears are stronger also, especially if you were to go to a lower gear set. Lower gearing means a smaller pinion, which is a weaker pinion, and less tooth contact with the ring gear. I guess that's why Ford 9" is so bullet proof!

Yes...I have the v-8. Happy to hear the engine is up to the task...33's are the biggest I will be going, probably. Just got it on Tuesday. Loving it so far in stock condition, but anxious to start the mods. Suspension first!!!

I haven't seen a swap either, thus the reason for this thread. Maybe I'll be one of the first, and if I do it, I will certainly document the hell out of it. From what my research shows so far, the 5th gen and 4th gen share identical chassis, etc. That's good news so far. I'm going to try to find a 5th gen to take some measurements to compare with my 4th gen. The saddest part of this is, I HAD a 5th gen trail edition, as you can see in my avatar. I traded it two years ago on a Caddy SRX. Then bought a Jeep Rubicon for off-roading. Sold the Rubi because I needed a larger vehicle for over-landing, thus the new '07 Runner.

The 8" in the 4th gen and the 8" in say a 1989 4runner are not the same. Yes, they measure 8" in diameter, but the carrier and housing are redesigned to be much stronger. I have never heard of a 4th gen rear end breaking, only wearing out from people failing to put oil into it. This can happen to any gear set.

I have done the Toyota Elocker retrofit into my 4th gen. The whole unit fits right in after you modify the housing. The best part is that you can use your original gears on the new elocker 3rd and not have to worry about gear break in or noise etc.

 

[SunPilot]

The 8" in the 4th gen and the 8" in say a 1989 4runner are not the same. Yes, they measure 8" in diameter, but the carrier and housing are redesigned to be much stronger. I have never heard of a 4th gen rear end breaking, only wearing out from people failing to put oil into it. This can happen to any gear set.

I have done the Toyota Elocker retrofit into my 4th gen. The whole unit fits right in after you modify the housing. The best part is that you can use your original gears on the new elocker 3rd and not have to worry about gear break in or noise etc.

I realize the two are not the same, although they are the same size. I also know the eLocker retrofit will work, but for a little more work and money I can have a beefier locker axle. Just thinking about it right now. BTW, I have read some stories of axle problems with bigger tires and heavy weight, not saying it is a common thing. I like to err on the side of caution, especially when I will be well off the traveled road.

 

[techno]

The 5th gen rear track is 1.2" wider than the 4th gen. Not a huge deal, especially considering many 4th gen people run wheel spacers or aftermarket rims with less backspacing, however it should be a big flag warning that some other geometry (importantly suspension bracket locations) may not be compatible. I'm sure you probably are going to anyway, but make sure to thoroughly compare all connection points on the housings and be ready to cut and weld if needed.

 

[SunPilot]

The 5th gen rear track is 1.2" wider than the 4th gen. Not a huge deal, especially considering many 4th gen people run wheel spacers or aftermarket rims with less backspacing, however it should be a big flag warning that some other geometry (importantly suspension bracket locations) may not be compatible. I'm sure you probably are going to anyway, but make sure to thoroughly compare all connection points on the housings and be ready to cut and weld if needed.

Yes, the track is wider, buy as you said, with front offset wheels it may end up being in proper alignment. The bracketry is the area of my concern. I have to find a 5th gen and take pics and measurements to see how the brackets and attachment points line up. It isn't my desire to cut and weld the brackets...if it turns out they are not in the proper locations, I will probably just go with an ARB or Toyota ELocker install.

 

[BusinessHippieRH]

You can break em... ask me how I know...

For moderate overlanding with 33s, you should be fine with the Toyota set-up. If you're going to be out crawling rocks and getting in to more technical stuff, you may want to upgrade, but at this point, a 5th gen axle won't be much of an upgrade...

There are two options for "bolt on" and they both come from Currie. The FJ Rock Jock 60 or Ford 9". I hear ECGS has a "hybrid 60" for our trucks now as well, but you would have to call them to get more information.

After I blew up my ring and pinion and it gnawed on the axles on the way out of the woods, I priced it all out. New everything but housing wasn't too much less to make it make sense to upgrade to the 60. (The Ox locker I'm tossing in changed the equation, but hey: if you're gonna upgrade, UPGRADE.)

It's FINALLY shipping today (8 weeks later- Currie seems to move at their own pace). Other than some FJ guys and the_josh, the only others that have done this swap have done a SAC on the front. I'll do my best to document what it takes to actually get it in there, but I'm not going to lie, my hands will be busy with tools most of the time.

 

[duffdog]

You can break em... ask me how I know...

For moderate overlanding with 33s, you should be fine with the Toyota set-up. If you're going to be out crawling rocks and getting in to more technical stuff, you may want to upgrade, but at this point, a 5th gen axle won't be much of an upgrade...

There are two options for "bolt on" and they both come from Currie. The FJ Rock Jock 60 or Ford 9". I hear ECGS has a "hybrid 60" for our trucks now as well, but you would have to call them to get more information.

After I blew up my ring and pinion and it gnawed on the axles on the way out of the woods, I priced it all out. New everything but housing wasn't too much less to make it make sense to upgrade to the 60. (The Ox locker I'm tossing in changed the equation, but hey: if you're gonna upgrade, UPGRADE.)

It's FINALLY shipping today (8 weeks later- Currie seems to move at their own pace). Other than some FJ guys and the_josh, the only others that have done this swap have done a SAC on the front. I'll do my best to document what it takes to actually get it in there, but I'm not going to lie, my hands will be busy with tools most of the time.

I'm curious to know what happened. How exactly did you blow up both the ring and pinion with an open diff? Running 40" tires? I rebuild 3rds, so I would like to hear any info you have.

 

[SunPilot]

I'm curious to know what happened. How exactly did you blow up both the ring and pinion with an open diff? Running 40" tires? I rebuild 3rds, so I would like to hear any info you have.

It will be interesting to find out!

 

[zidaro]

Here ya go! Beef and bolt in.
This is the route i go once i pop my rear cherry (that doesn't sound right?)

9.5 FJ Cruiser/4Runner Diamond Axle - Front Range Off-Road Fabrication

as for your question of the bracketry lining up on a simple housing swap-
Id also utilize Brians (FROR) knowledge and willingness to help- he will know if the 4th/5th gen geometry is retained. Im thinking it is, since the 2 generations share the exact same suspensions and frames. Id assume that the 1.25" extension is happening at the axle ends.

 

[SunPilot]

Here ya go! Beef and bolt in.
This is the route i go once i pop my rear cherry (that doesn't sound right?)

9.5 FJ Cruiser/4Runner Diamond Axle - Front Range Off-Road Fabrication

as for your question of the bracketry lining up on a simple housing swap-
Id also utilize Brians (FROR) knowledge and willingness to help- he will know if the 4th/5th gen geometry is retained. Im thinking it is, since the 2 generations share the exact same suspensions and frames. Id assume that the 1.25" extension is happening at the axle ends.

Looks like something from a Mad Max movie! LOL

 

[BusinessHippieRH]

I was trying to climb a large boulder (~4ft diameter) on the passenger side only. Got the front over it using a little momentum, but rear kept getting stuck trying to crawl it. Finally gave it hell and got over it with some gassing, but didn't let off the gas quick enough when I finally cleared it (no moment of victory pause- just straight up and over).

I didn't have a locker in there yet, so driver rear tire slowly turning, passenger tire spinning quick as it jumped up and over. Then it came to a sudden dead stop when it hit solid ground again. Loud pop and snapping noises.

That being said, my truck has full belly skids, a rear bumper, and was loaded for a weekend of camping. Plus I run 295s... she's heavy.

The damage:
Ring:

Pinion:

Leftovers:

 

[SunPilot]

Wow, chewed that right up!

 

[duffdog]

I was trying to climb a large boulder (~4ft diameter) on the passenger side only. Got the front over it using a little momentum, but rear kept getting stuck trying to crawl it. Finally gave it hell and got over it with some gassing, but didn't let off the gas quick enough when I finally cleared it (no moment of victory pause- just straight up and over).

I didn't have a locker in there yet, so driver rear tire slowly turning, passenger tire spinning quick as it jumped up and over. Then it came to a sudden dead stop when it hit solid ground again. Loud pop and snapping noises.

That being said, my truck has full belly skids, a rear bumper, and was loaded for a weekend of camping. Plus I run 295s... she's heavy.

The damage:
Ring:
View attachment 224266
Pinion:
View attachment 224267
Leftovers:
View attachment 224265

It looks like the pinion went and started grinding down the ring gear. I can see that not all the teeth on the ring are broken. Which is consistent with your story of hitting the gas and the wheel stopping immediately. In your case I don't think you would have broken anything if there was a locker or spool in that case and you were crawling normally. But you are right, anything can break if abused.

 

[BusinessHippieRH]

Duffdog: I agree with you completely about a locker would have solved this problem. Hence why I'm real happy to be getting that Ox locker in the rear. From what I see, it looks more like a bunch of tension got placed on both the pinion and the ring gear and teeth let loose on both at the same time (when rotated to match, the missing teeth line up pretty well).

Unfortunately, Toyota thinks these axles are made of gold. And, while they're great axles, they just don't match my eventual plans for the build.My plans are a SAC up front (another 60-not likelyto be Currie after dealing with 2x longer than told lead time) and 37s. The stock axles simply won't hold up to that. I just figured, why not go ahead and upgrade the rear, and when the time comes, I'll just cut off all of the "stock" brackets and weld on new ones that match the front geometry/capabilities.

 

[duffdog]

Duffdog: I agree with you completely about a locker would have solved this problem. Hence why I'm real happy to be getting that Ox locker in the rear. From what I see, it looks more like a bunch of tension got placed on both the pinion and the ring gear and teeth let loose on both at the same time (when rotated to match, the missing teeth line up pretty well).

Unfortunately, Toyota thinks these axles are made of gold. And, while they're great axles, they just don't match my eventual plans for the build.My plans are a SAC up front (another 60-not likelyto be Currie after dealing with 2x longer than told lead time) and 37s. The stock axles simply won't hold up to that. I just figured, why not go ahead and upgrade the rear, and when the time comes, I'll just cut off all of the "stock" brackets and weld on new ones that match the front geometry/capabilities.

In your case, an 80 series cruiser front axle might be available a lot faster. Just get some good knuckles, a front high pinion elocker and you should be good to go.

 

[swiftneed]

blown diff not sure

I'm curious to know what happened. How exactly did you blow up both the ring and pinion with an open diff? Running 40" tires? I rebuild 3rds, so I would like to hear any info you have.

Well I yet have to open up my diff cover but this weekend I blew my diff so I am looking which way to go and reading up any input would be greatly appreciated, I have a V8