The Honda Civic series utilizes a transaxle arrangement where the transaxle and the differential are contained within the same housing. Power is transmitted from the engine to the transaxle and in turn, to the differential. The front drive axle halfshafts transfer the power from the differential to the front wheels.
The GW transaxle is a five-speed version of the GV four-speed transaxle. They consist of mainshaft and countershaft assemblies, synchronizer assemblies, shift forks and a differential. A reverse light switch is incorporated into the unit to complete the reverse light circuit when backing up.
The L3 Series four-speed and five-speed of 1988-91 and the S20 series five-speed of 1992-95 are later versions of the GW transaxle.
The 1985-87 Civic Wagon 4WD employs a modified version of the conventional five-speed. Under normal usage, the vehicle operates in the same manner as other Civics in 2WD, transmitting the engine's power through halfshafts to the front wheels. When the 4WD mode is engaged, power is transmitted to the rear wheels through the use of a transfer case.
The 1988-91 Civic Wagon 4WD employs a viscous coupling that engages the rear wheels as needed, depending on front wheel traction. This "Real Time 4WD" system is intended to make power transfer between 4WD and 2WD essentially automatic. The viscous coupling unit is mated to the front of the driveshaft which connects to the rear differential. Inside the unit's housing are 79 plates, which have 0.0078 in. (0.2mm) of clearance between one another, surrounded by silicone oil. Forty of these oil-bathed plates are splined to the housing, and 39 are splined to the shaft in alternate succession. Whenever the front wheels lose traction and spin faster than the rear, the friction (and pressure) in the viscous coupling forces the plates to drag, engaging the rear wheels as needed. Once engine torque is delivered to the rear wheels, front and rear wheel traction stabilizes and the wheels begin to turn at the same speed. As this happens, the temperature of the silicon oil and the pressure in the viscous coupling unit decreases and the power to the rear wheels decreases proportionately.