"D", "4", "3" Positions 2nd Gear

WARNING: This page is about a different car, the 2005 Infiniti QX56. However, it is still accessible from the selected car via links, so may be relevant.

The forward brake and the forward one-way clutch regulate reverse rotation of the mid sun gear.
The 3rd one-way clutch regulates reverse rotation of the front sun gear.
The direct clutch is coupled and the rear carrier and rear sun gear are connected.
During deceleration, the mid sun gear turns forward, so the forward one-way clutch idles and engine brake is not activated.

Fig 1: Power Transmission Diagram - "D", "4", "3" Positions 2nd Gear
Courtesy of NISSAN MOTOR CO., U.S.A.