8.7" front E-locker diff for 200 Series. (1 Viewer)

[bjowett]

The decision has been made to concoct a front E-locker for the 200 Series Land Cruiser that is in the stable.

First the whys... Most of the parts to build it already exist. I like the factory e-locker design. It's fairly reliable, and if it does have issues, they can be dealt with trail side. Now I realize the 80 Series rear 1.31" 30 spline version of this locker has been known to twist the shaft and create a situation where the dog clutch can no longer slide, especially when used heavily with large tires. The front jackshaft on the 8.7" differential is a 34 spline 1.39" diameter unit. It's far beefier, and operates in a less abusive application.

How. The 200 is AWD, so the front differential is a clamshell IFS with jackshaft.

Now, the 2nd Gen Tundra is based on the LC, so it shares the front differential size and design. The major difference is that it has a part time system. Being part time, it uses the differential disconnect system to engage/disengage the 4x4. The actuator in this system works in an identical fashion to an e-locker, same motor drive, signals, and all. It mounts on the jackshaft housing, and normally connects/disconnects the right side axle shaft to engage/disengage the differential. The actuator is in the perfect place to use, for those familiar, a splined shaft and dog clutch to create an e-locker.

Housing comparison.

Tundra jackshaft housing on LC diff w/ LC jackshaft. The LC jackshaft maintains an OD of 1.393" for the entire length. This will allow the shaft to have the 34 splines cut further down the length of the shaft, thus giving the dog clutch an appropriate splined area to ride on.

Jackshaft showing actuator fork location. The shaft will be splines here.

This picture shows the dog clutch. It slides right into the diff housing and will engage the differential body, locking the shaft to it, and creating a locker. This is a 1.31 FZJ80 unit, plenty of material to have it made in a 1.39" 34 spline piece.

Now the the tougher part of this. Teeth for the dog clutch to engage need to be created. I may try to find a way to add them to the existing differential, or machine a whole new differential unit. Thoughts and ideas on this are welcome.

 

[canisearch]

Interesting...with both the 8" and 9.5" style requiring oversized carrier bearings and corresponding oversized carrier journals on that side to work, i am assuming space for making lugs/splines on the carrier is limited...do you know the dimensions for that side carrier journal yet?

 

[cody c]

too cool!

Is that diff housing aluminum? I was looking at the god winches the other day and they seem a bit heavy, just thinking these would be better then the 4runner diffs if they are lighter.

 

[bjowett]

Yes, the side journal on the 8.7" is 58mm, The 9.5" e-locker journal is only 2mm larger at 60mm. Despite being nearly the same size, I'm going to use much of the 9.5" differential design.... essentially, I'll be installing the 8.7" ring gear on a 9.5" case. The case diameters are also only a few millimeters different. The 4 pinion spider internals will then be easy to utilize. The 9.5" e-locker carrier bearings are 95mm OD, vs 90mm for the 8.7", so there looks to be (preliminary) more than enough material in the aluminum housing to support the larger diameter bore. No matter though, the weakness lies else wear, and I'll be adding a truss to the housing, as I've seen Tundras with large tires and heavy throttle application blow the aluminum case.

Which year 4-Runner diff is used for the deity winch? The 8.7" diff, complete with jackshaft, weighs about 74lbs.

 

[canisearch]

Wow! Those are encouraging measurements...so if i understand the rest of the plan...

1. Take a 9.5 elocker carrier...80 style or 100 style?
2. Machine the side gears out to 34 spline...
3. Bolt on 8.7 ring gear...bolt pattern? Distance to pinion CL adjusted with spacer or shims?
4. Machine the alumium housing to fit the 95mm OD bearings...shims on carrier side of bearings? Total width of carrier isn't a problem?
5. Build something to strengthen the aluminum housing.

I am excited to see the results...

 

[cody c]

Not sure about which diff they use, I think just an 8" out of an ifs 4runner.

As for what sides the shims are on as per posted above, are they not the same adjustable type as in the 9.5" thirds?

 

[bjowett]

The width of the carrier IS a problem, the 8.7" is roughly 15mm wider at the carrier bearings, so dropping the 9.5" in would not work. Additionally, the dog clutch is wrong side of the carrier. One saving grace is that the side gears of both units sit at nearly the same width... I'm brainstorming how to remedy this, and have and idea or two to hash out.

The older 80 style 9.5" carrier will be utilized (or parts from it). The 30 spline side gears have enough meat in them to be taken out to the 34 spline size.

The 12 bolt pattern of the old style 9.5" is very close to the 12 bolt pattern of the 8.7", but that's a no go. The solution to this may lie with the solution to the carrier width.

Machine the aluminum housing, yes.

Yes to number 5.

Cody, yes, the 8.7" is adjusted with shims, just like the 9.5" e-locker.

 

[canisearch]

Thanks for the clarifications...i hope you keep us updated on your solutions to the remaining obstacles...whenever i see you post up a new project, i hope to see you use a machined component to rival the flywheel for the 6 speed tacoma transmission swap...perhaps this is the project?

 

[bjowett]

Time to bring this up from the back burner.

 

[elkaholic]