Missing element: 44852 (BL: x928cx1) - Technic Axle Connector Rectangular Triple Spring-Loaded
I also suggest you to use one longer 4L cardan U joint for the rear axle.
And dont forget about roboriders discs for brakes.
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Use LEGO Digital Designer to open these files and generate step by step building instructions.
This MOC also has a 3D digital file available (eg LDD, MPD, etc): 3D Model