Pondering a rear locker

[jiggletits]

..Because I'm an idiot and go places I shouldn't go. Not rock crawling, mostly hunting trips. Not abusing the truck badly, and not running huge tires. I'm on 265/65/17 currently and wouldn't ever go bigger than 285/70/17s.

I went with electronic front/rear lockers on my Tundra. Eatons, regeared for 35s. Those work great and have gotten me out of situations where A-TRAC didn't cut it. Not sure how the ATRAC compares on the GX.

Not interested in air lockers, never have been. Too much muss and fuss with compressor/lines/etc and the internal seals can go out. I want something that will last another 200k+ miles trouble free.

Would you guys get a new OEM FJ Cruiser rear third member? Or the Eaton electronic locker? FJ cruise seems like a good drop in unit, pre-assembled so no messing around with the carrier/shims/gearing. Plus it's Toyota so it will last.

I'm also a little confused on which rear end is which. Eaton lists two different 8" versions and an 8.2" version. What did the GX come with through the years? Are all FJ rear ends interchangeable?

OR is this all moot? Is A-TRAC so great on this that I shouldn't at all? The Tundra is over 8,000 lbs with the FWC in it so lockers there make a bigger difference.

Thanks in advance

 

[HomersCanyonero]

All Gx470s come with 8” rear diff.

I saw a YouTube video of a guy complaining that the electronic Eaton would disengage if you went backwards (reverse) when finding your line. He was pretty upset about that but I don’t know how old that video was. Just research that.

The stock oem 8” rear diff is a weak point. Upgrade to an 8.2” rear diff. This might require modifying the front diff as well. This part I’m a little confused on what’s needed in the front if you upgrade the rear to 8.2” (beefier).

 

[HomersCanyonero]

Oh you had Eatons. Did they disengage on reverse?

 

[jiggletits]

Oh you had Eatons. Did they disengage on reverse?

No, that sounds odd. I mean, I'm talking about a 10.5" rear end in the Tundra, not an 8" or 8.2" so it may be built differently. I think Eaton makes 3 or 4 different mechanisms that go into different e-lockers.

I wonder how he had it wired... I've been wanting to wire mine so they only come on in 4 Low. Depending where he pulled his 12v signal for the switch... he could only be getting power to it in drive.

 

[jiggletits]

All Gx470s come with 8” rear diff.

I saw a YouTube video of a guy complaining that the electronic Eaton would disengage if you went backwards (reverse) when finding your line. He was pretty upset about that but I don’t know how old that video was. Just research that.

The stock oem 8” rear diff is a weak point. Upgrade to an 8.2” rear diff. This might require modifying the front diff as well. This part I’m a little confused on what’s needed in the front if you upgrade the rear to 8.2” (beefier).

Beefier isn't much of a concern, ease of install is higher priority. Not looking for any more "beef" than a stock 4Runner Off Road.

The FJ rear end seems like the least labor intensive move, but does the 3rd member fit right in? Or do I need the whole axle? If whole axle, then Eaton in the 8" might be easier.

 

[HomersCanyonero]

There’s reports of the 8” in early 2007-09 FJCs and some GX470s exploding in harsh offroading situations. So, in 2010 Toyota upgraded to 8.2” diff on GX460, FJC and 4Runners.

 

[Rednexus]

ATRAC on aired-down tires works pretty well. I've wheeled a lot with it here in MO and it did great in CO/UT this summer. Lockers are not "needed" but are definitely better than ATRAC as they are proactive, not reactive, and help hold momentum. If you aren't airing down ATRAC works very poorly.

Probably the "easiest" way to do this is to get a complete 8" third member with a Eaton locker from East Coast Gear Supply. They have a 5-year warranty and operate on a core basis. The cost is around $2K for the front and $2K for the rear. Swapping the rear 3rd member appears pretty easy, and the front swap doesn't appear terrible either. A used Toyota e-locker 8.2 rear axle from a FJ or 4Runner is going to cost at least $2k, have no warranty, and be more work to swap and wire than going with a prebuilt 3rd member.

I eventually plan to go this triple-locked route along with a 4.30 reargear when my 32" tires wear out and I'm ready to upgrade to 33's.

 

[TheLCProject]

From what I understand, that video on the Eatons disengaging when switching from drive to reverse is a little overblown. Sure, by their design they disengage, but it'd likely only be an issue for the hardcore crawlers out there.

The lack of air lines would be enough of a benefit for me.

 

[HomersCanyonero]

Here’s a thread with good info on axles and diffs

 

[rommelrommel]

Beefier isn't much of a concern, ease of install is higher priority. Not looking for any more "beef" than a stock 4Runner Off Road.

The FJ rear end seems like the least labor intensive move, but does the 3rd member fit right in? Or do I need the whole axle? If whole axle, then Eaton in the 8" might be easier.

You either need the whole axle, or you need to drill and tap extra holes in yours.

Most people will say the 8" won't last if you're doing stuff that warrants a locker.

The easy way is a 8.2 elocker complete axle. It's a straight and easy swap, everything bolts up. There are a couple people that make plug and play harnesses with a factory toyota locker switch that goes in the blank plate near the steering wheel.

If you have KDSS it's actually easier to find as 5th gen 4 runner trails have the e-locker and KDSS. If not there are some other 8.2 elockers with the right gearing, but they're scarcer and in more demand.

 

[HomersCanyonero]

Here's additional diff info from the GXOR Knowledge-base

• Stock 8“ rear with improved ring and pinion.
• Stock 8” rear with improved ring and pinion and axles.
• 2010 or later FJ 8.2“ rear axle replacement (whole housing and diff) - Bolt on without KDSS
• 2010 or later 4Runner 8.2” rear axle replacement (whole housing and diff) - Bolt on with or without KDSS, depending on 4Runner trim (Trail Premium w/KDSS will bolt on to a GX470 w/KDSS)
• 2010 or later GX460 8.2“ rear axle replacement (whole housing and diff), will only fit KDSS GX470's or will require rear sway bar removal or bracket fabrication. Swapping to a GX460 rear axle will also require re-gearing to match factory 3.73, or regearing the front to match 3.91 (doable by replacing the front diff with a ~$100 junkyard GX460 unit)
• Aftermarket 8.2” rear axle replacement (whole housing and diff) - Bolt on
• Aftermarket 9.5“ rear axle replacement (whole housing and diff) - Bolt on

 

[HomersCanyonero]

If my 2003 GX470 rear diff breaks into pieces...I'm going to have a bigger dilemma... (1) fix it with an 8.2" e-locked rear... (2) part the 470 and move to a 460...(3) cry and go home.