The Mechanics of Locking the Center Diff.

[Untamed]

When we lock the center differential, what is actually happening mechanically? I know the front and back are split 50/50 but does anyone know what/where this is happening. I assume the transfer case is locking some gears together?

[bulldog]

There is an electric actuator that pushes a fork forward. The fork is in the transfer case and connected to a sleeve with splines on it. This sleeves effectively connects the 2 parts of the planetry gear (center diff) together that basically connects the front and rear drive shafts together to work at the same speed.

Saying splitting the Torque 50/50 is not really correct as the true amount of torque on the dirveshafts will be determined by the resistance of each axle. It just makes sure that the axles turn at the same speed irrespective of the axle load.

The diff mechanism looks different in the transfer case to a front or rear diff, but works on the same principal. SO the diff lock works the same as well, by locking the output shafts together to work at the sae speed.

Also keep in mind that the center diff is a Torsen diff with a limited slip application bu using gears.

[my034runner]

Andries,
You're some type of super genius or something. You pretty much hit on the head. Toyota's explains it as :
"Torsen Limited slip Center Differential can sense if one or more wheels lose traction, and then redistributes torque to the front wheels or the rear wheels as needed"
Go to http://www.toyota.com/vehicles/2006/4runner/key_features/limited_slip_diff.html?noreloadredir to see the animated demo of how it works. It definitely is a great feature!!
:devil: :beer: :rockon:

[bulldog]

Don't know about genius, I'm only a genius when drunk :drink: :jester:

Just to make the distinction. The 4R has a Torsen center diff, which works like a limited slip diff and distributes the torque based on application, with the ratios listed per Toyota. It never allows all the torque to go to one axle. This is normally used when driving on slippery surfaces and works with VSC. Mark and I can attest that it works wonders at high speed on gravel roads in Death Valley.

Next when you lock the center diff it actually disables the center diff as well as VSC. Used for dune driving and harder trails. It uses the mechanism I described above to have both driveshafts turn at the same speed, so your front and rear axle will always work at the same speed. However saying it splits Torque 50/50 is not truely correct as the axles only turns at the same speed, but torque on the driveshaft will be determined by the resistance offered of the traction that axle has. The reason why rear axles are normally more beefy that front ones, as you mostly use the most torque going uphill and your rear has more weight on it then thus more ability for traction.

Dont worry too much about the last piece, rather just keep in mind both driveshaft will turn at the same speed with the center locked.

[Untamed]

A ton of thanks! This is realy helpful!

[my034runner]

A ton of thanks! This is really helpful!


Now that you are armed with your new found knowledge, go use it!! It's about time to wheel in that muther!
:jester: :moon: