unlocked front diff bolts (10) vs. locked front diff bolts (11)

[landcruiser3DP]

why is there 10 bolts in an unlocked front diff and 11 on a locked front diff please?

also, aside from the harness and the locker switch - converting to OEM locked requires a front and rear locking differential? what else?

edit: links here:

Retro fit Locking Diff to Non Locked Housing

forum.ih8mud.com

Outdoor Recreation Network - Off-Highway, Jeep, and 4x4 Fun

Toyota Tech: Installing a Toyota Electric Locker

www.4x4wire.com

lx450 rear locker wiring

forum.ih8mud.com

retro-fitting OEM lockers -Wiring Harness

forum.ih8mud.com

Rear Factory Locked Axle Shaft Mod

I wanted to share some knowledge that I acquired from a friend regarding modifying your rear passanger side axle shaft. This will allow you to remove the twisted portion of the axle shaft if it breaks under load. My friend Kenny documented the process and dimensions where to modify the shaft...

forum.ih8mud.com

 

[Grandlooser]

The axle housing itself is also needed unless you want to do a bunch of fab work.

 

[landcruiser3DP]

The axle housing itself is also needed unless you want to do a bunch of fab work.

thanks. what is the fab work exactly please? or do i search for “locked diff conversion with unlocked axle” or something?
also. why is the axle different exactly? i’m not quite following (most likely because i don’t really understand what the inside of a differential looks like?).

 

[Grandlooser]

There is a large notch in the housing so that the different locking diff housing can go in and out. Also 2 of the studs are very long. It's not a s*** load of work and I would do it myself. However I have a Bridgeport and lathes and all the necessary goodies. Despite that I still opted for a locked 80 to start.

Edit: I think the 2 long studs are also in a different pattern than non locked, so you will also have to drill and tap for those after notching. Do you have a locker in the rear yet?

 

[landcruiser3DP]

There is a large notch in the housing so that the different locking diff housing can go in and out. Also 2 of the studs are very long. It's not a s*** load of work and I would do it myself. However I have a Bridgeport and lathes and all the necessary goodies. Despite that I still opted for a locked 80 to start.

Edit: I think the 2 long studs are also in a different pattern than non locked, so you will also have to drill and tap for those after notching. Do you have a locker in the rear yet?

no front or rear locker. i just kind of wanted to understand what is up with this and squirrel it away in case an opportunity arises.

so i would like to understand it. and print out a thread that shows how to do it.

but also for instance, i guess there is a good reason to have two different axles? i mean it is not so someone does not come in on a monday morning and accidentally install a locked diff in an unlocked housing (or vice versa) at the factory or something - is it?

 

[Grandlooser]

I honestly have no idea why they were not all locked. It's Toyotas flagship off-roader so IMO it should have been standard.

 

[landcruiser3DP]

I honestly have no idea why they were not all locked. It's Toyotas flagship off-roader so IMO it should have been standard.

got you. i think what i was curious about was why not make a locked axle and put a unlocked diff in there? or even bolt a baffle with a gasket or something in there if thing were too sloppy without the rest of the locked diff? it’s probably a very dumb question it just seems like a lot of work to make two very similar axles. but i am definitely not very knowledgeable about this stuff.

 

[Grandlooser]

I don't think that's dumb to ask. I often think of these kinds of things myself. A single type of axle housing would make much more sense to me.

 

[-Spike-]

why is there 10 bolts in an unlocked front diff and 11 on a locked front diff please?

also, aside from the harness and the locker switch - converting to OEM locked requires a front and rear locking differential? what else?

View attachment 2434538

It's probably either a misprint or they use a different fastener in the 11th hole on an unlocked diff. I converted my unlocked housing for a locked diff, all it takes is removing some material and relocating two four holes.*

*Edit- Some of the studs are in a different pattern and there is one more on the locked axle, see pics in post #13. You actually have to drill and tap 4 holes.

What I find interesting is my 94 FSM doesn't specify how many, and has a different torque spec, 18 vs. 20. Which is nice, because I always torque mine to 20 anyway.

 

[sunrk]

I honestly have no idea why they were not all locked. It's Toyotas flagship off-roader so IMO it should have been standard.

Lockers are not necessary. Neither is 4wd mode. You use them to get yourself *out* of trouble, not into it.

But are Toyota's factory lockers any good? I've driven my 80 on a lot of knarly stuff and not needed lockers but I don't doubt they have their place to make the driveline more versatile.

 

[Grandlooser]

Lockers are not necessary. Neither is 4wd mode. You use them to get yourself *out* of trouble, not into it.

But are Toyota's factory lockers any good? I've driven my 80 on a lot of knarly stuff and not needed lockers but I don't doubt they have their place to make the driveline more versatile.

It's night and day man. You are guaranteed only 2 wheels with power in 4wd with open diffs. 3 wheels guaranteed with rear locked, that's exactly 50% more. And of course all 4 with both locked. Lockers can definitely prevent as many or more situations than they can get you out of. Not to mention making a lot of situations much less dramatic and allow traversing obstacles to be a lot less stressful on the vehicle.

 

[-Spike-]

also, aside from the harness and the locker switch - converting to OEM locked requires a front and rear locking differential? what else?

I missed this question the first time around. You need the switch, diffs and wiring to get to the body, and unless you have an LX you need to run wires to the rear. You also need the locker ECU and the long short side rear axle, at least. Not positive that's all, as its been 15 years since I converted mine.

There are several threads on this, if you are interested in learning more about it.

 

[richardlillard1]

It's probably either a misprint or they use a different fastener in the 11th hole on an unlocked diff. I converted my unlocked housing for a locked diff, all it takes is removing some material and relocating two holes.

What I find interesting is my 94 FSM doesn't specify how many, and has a different torque spec, 18 vs. 20. Which is nice, because I always torque mine to 20 anyway.

View attachment 2434783

Different casting because of the locker actuator. Looking at it from the rear, the 3 o’clock stud is removed and two longer studs are added for the actuator part of the third.

Unlocked:

Locked:

 

[-Spike-]

Different casting because of the locker actuator. Looking at it from the rear, the 3 o’clock stud is removed and two longer studs are added for the actuator part of the third.

Unlocked:
View attachment 2435004

Locked:
View attachment 2435010

I guess I actually had to drill and tap 4 holes then. Makes sense.

 

[landcruiser3DP]

Different casting because of the locker actuator. Looking at it from the rear, the 3 o’clock stud is removed and two longer studs are added for the actuator part of the third.

Unlocked:
View attachment 2435004

Locked:
View attachment 2435010

thanks man.

are you referring to “third member” when you say “actuator part of the third”? i don’t quite follow any of that actually.

also, why wouldn’t they use the locked housing slash pumpkin and just use shorter bolts on the unlocked model?

or what has to be done again to the unlocked axle and pumpkin to get the locked diff on it again please?

 

[landcruiser3DP]

I guess I actually had to drill and tap 4 holes then. Makes sense.

did you drill and tap with a jig or freehand or what?

 

[landcruiser3DP]

I missed this question the first time around. You need the switch, diffs and wiring to get to the body, and unless you have an LX you need to run wires to the rear. You also need the locker ECU and the long side rear axle, at least. Not positive that's all, as its been 15 years since I converted mine.

There are several threads on this, if you are interested in learning more about it.

help me here please?

you need:
front locked diff
rear locked diff
round locker switch
wiring to rear axle (or have the LX)

what is:
wiring to get to the body? this is diff to connector somewhere in the body wiring.
ECU?
long side rear axle?

i’ll go looking for a thread and post it here if i can find a good one. maybe the faq will have a good one i guess.

 

[-Spike-]

what is:
wiring to get to the body? this is diff to connector somewhere in the body wiring. The harness from the diff to the body.
ECU? There is an electronic control unit that controls the lockers, similar to the engine ECU.
long side rear axle? Sorry, my mistake, it's the short side. Can't remember s***. The short (passenger's) side rear axle shaft is different on locked trucks, the splines are cut a bit longer than the unlocked version. While you're there, do this mod to the shaft.
You also need several of the studs.
You may also want the locked diff gaskets to use as a pattern for what needs to be removed from the housings. Personally, I don't use them to assemble the diffs, I prefer RTV.

See responses inline.

did you drill and tap with a jig or freehand or what?

I removed the studs that weren't needed, placed the diff in the housing on the remaining studs, and used the holes in the diff as a drill guide. I use a bit that just barely fits in the diff hole to start, to create a divot that centers the correct bit for the tap. Then drill through with the right size bit, pull off the diff, and tap the threads.

Don't rely on my responses though, I often misremember stuff (as evidenced already). There are, as I mentioned, several threads detailing this job.

 

[landcruiser3DP]

See responses inline.


I removed the studs that weren't needed, placed the diff in the housing on the remaining studs, and used the holes in the diff as a drill guide. I use a bit that just barely fits in the diff hole to start, to create a divot that centers the correct bit for the tap. Then drill through with the right size bit, pull off the diff, and tap the threads.

Don't rely on my responses though, I often misremember stuff (as evidenced already). There are, as I mentioned, several threads detailing this job.

THANKS spike. i added the link to the list of links i edited into the original post. APPRECIATE the help. i've got some reading to do which is great...

 

[WarDamnEagle]

You need the diff lock differential gasket as well. I installed two TRD elockers in a 4Runner and did everything by hand. It isn't that hard to do. The diff lock gasket is a good pattern for the modifications and of course needed to assemble.