NISSAN L3N71B – ATSG (Automatic Transmission Service Group)
NISSAN L3N71B – ATSG (Automatic Transmission Service Group) PDF. The Nissan L3N71B transmission is a three speed reardrive automatic with a converter clutch. The teardown-assembly and trouble-shooting of this unit is covered in detail.
The L3N71B transmission is a fully automatic unit consisting primarily of a 3 element hydraulic lock-up torque converter and two planetary gear sets. Two multiple-disc clutches, a multiple-disc brake, brake band, and one-way clutch provide the friction elements necessary to obtain the desired function of the two planetary gear-sets.
A hydraulic control system is used to operate the friction elements and automatic shift controls.
LOCK-UP TORQUE CONVERTER
The lock-up torque converter is attached to the crankshaft through a flexible drive plate and serves to directly couple the turbine runner and pump impeller through the lock-up piston which is controlled by the speed cut valve and lock-up control valve. Heat generated in the torque converter is dissipated by circulating the transmission fluid through an oil-to-water type cooler in the radiator lower tank.