Abstract: A 5-speed automatic transmission for a vehicle having a highly efficient top gear, a compact construction and a wide overall range of gear ratios. The automatic transmission has a speed changer which provides five gear stages, namely two speeds on the speed decreasing side and two speeds on the speed increasing side with a direct-coupled gear therebetween. The speed changer includes a ring gear connected to an output shaft, a first carrier, a first sun gear, a second carrier connected to the first carrier, a stepped pinion gear supported by these two carriers, and a sun gear meshing with the pinion gear. The first carrier is connected to an input shaft by a clutch and the first sun gear is connected to the input shaft by a clutch. The first sun gear may be stopped by a first brake, a second brake stops the second sun gear and a third brake is provided to stop a third sun gear. Top gear is achieved by meshing of the pinion gear with the second sun gear and the ring gear.

Abstract: An automatic transmission for five forward speeds equipped with a main transmission mechanism and an auxiliary transmission mechanism. The auxiliary transmission mechanism includes a multi-disc clutch and a hydraulic servo therefor arranged in a first planetary gear set. The first planetary gear set includes a first ring gear connected to an output unit of the main transmission mechanism and a first carrier connected to an output shaft and further to a first sun gear through a multi-disc clutch and a hydraulic servo for the former. The hydraulic servo for the multi-disc clutch is connected to an integral casing through a band brake and is arranged around the outer circumference of the hydraulic servo for the multi-disc clutch.