D-MAX Upper Center Transmission Case SD-302DU for D-MAX by Yokomo  [SD-302DU]

Upper Center Case: Overview and Purpose

This Yokomo SD-302DU upper center transmission case is a machined aluminium replacement housing compatible with D-MAX standard parts. It secures the top half of the center transmission assembly, helps preserve consistent gear mesh, and creates a robust mounting surface for shafts and bearings.

Fitting is straightforward: remove the stock upper case, transfer the original bearings and internal gears, then install the SD-302DU and torque fasteners while checking gear mesh and shaft alignment. Keep original bearing sizes and fastener routes to avoid altering drivetrain geometry.

As a tuning upgrade, the stiffer aluminium upper case reduces flex under load and improves access for maintenance. That rigidity helps maintain gear alignment during hard use and makes repeatable adjustments easier when setting up or servicing on the pit bench.