DCCD stands for Driver Controlled Center Differential. Explanations for this system are complex and tend to go about like this.
Basic Idea Behind DCCD
If nothing else below makes sense, remember this: it's all about slip. Slip refers to how much difference in speed is allowed between the front and rear wheels. More slip is good for cornering, while less slip is better for acceleration and traction due to the equal power distribution.
How does the DCCD work?
The DCCD refers to the ability to adjust the clutch packs in the center diff to get them to grab or not grab, which determines how much of the power created by the engine is transferred between the front and rear wheels.
When the center diff is open, the clutch discs touch but slip against each other, which is where the term "slip" comes into play. Slip refers to the difference in rotational speed between the front and rear wheels or axles.
When there is no slip (locked), the front and rear axles rotate at the same speed. This typically means the center differential is locked or nearly locked, providing maximum traction and stability, which is useful for off-road or snow, or hard acceleration.
When there is slip (open), the front and rear axles can rotate at different speeds. This happens when the DCCD allows a more open differential setting to improve handling and reduce drivetrain binding during turns or normal driving.
When there is no input to the center differential, it defaults to an open mode or maximum slip. This allows power to transfer from the front to the rear through the slipping clutch packs in the center differential. While this is not a problem when cruising the highway, it can become an issue during hard acceleration. Additionally, it may pose a serious concern on the dyno due to the increased force required to spin the rollers.
What does a DCCD Controller like iDCCD do?
The iDCCD system functions similarly to an OEM controller by utilizing various sensors, such as wheel speed sensors, yaw rate sensors, and throttle input, to detect any slip between the front and rear wheels. This system is connected to physical switches located in the center console, allowing the driver to select their desired settings. It is essential to note that the switches on the dashboard do not communicate directly with the transmission; instead, a controller is required to manage the adjustment of the center differential.
Most other aftermarket units do not rely on slip and just utilize a standard output to lock and unlock the center differential based on the inputs it sees. The trouble with this control method is that it does not account for temperature changes in the center differential over time, which adjust the amount of lockup at a given controller output setting.
Based on the detected slip, the system can automatically adjust the locking ratio of the center differential by activating an electromagnetic that pulls the clutch packs together (lock/no slip) or turning off the electromagnet (no lock/slip)
There are options for driver control in certain situations, but generally, it's best to let the DCCD controller do its job for performance.
You want a DCCD controller connected so that when accelerating hard, the controller commands the clutch packs to "lock up" so they don't slip against each other. Locking them together reduces friction, heat, and wear and tear on your center diff. When accelerating hard without the clutch packs pulled together, they create far more friction than they were designed to handle, which causes premature wear.
