Is there any ways to help speed up the disassembly process for big LEGO Technic set such as the 42043 Mercedes-Benz Arocs?
Most Technic models are built in a modular fashion. This particular model (42043 Mercedes-Benz Arocs) is no different, from the instructions you can tell it has been built in the following order: Engine/Chasis, Cab, Wheels, Truck Bed and finally the Crane.
Large sets often use red pins to join together major components. Therefore the best way to deconstruct a Technic set is to do exactly the opposite and work your way back through the instructions or at least the 'major components'.
Major components (for lack of a better term) are usually highlighted in the instructions and typically have their own numbered bags. Below you can see the truck bed.
The truck bed consists of a number of sub-components such as the truck outrigger.
Working backwards through the instructions you can either tackle the disassembly on a piece-by-piece basis or on each sub-component.
Use a Pin Pusher
Disassembling Technic models has always been a painful experience for me, particularly on my thumbs when removing the many, many pins and axles used.
I like to use a 'Pin Popper' to easily remove most pins. It's essentially a axle (Generally the longer the axle the better). I like to put a few Brick, 'Round 2 x 2 with Axle Hole' at one end to use as a handle and to stop the axle digging into the palm of my hand.
I have also started to use an alternative pin-pusher design to speed up the process.
Maybe you can use some techniques using the LEGO parts to avoid breaking it. You can use pieces to make your own "tools" to make disassembly process faster...
Here's an example of this.