Manual Transmission/Transaxle: Description and Operation

The Getrag-designed manual transmission, installed in both the 4X2 and 4X4 models, has five forward speeds and reverse. The transmission is fully synchronized in all gears, including reverse. There are four separate gear carrying shafts: the input shaft, mainshaft, countershaft, and reverse idler shaft. The forward end of the mainshaft is supported in a needle bearing that is installed in the rear end of the input shaft. When fourth gear is selected, a clutch hub mechanically links the input shaft directly to the mainshaft. There are no meshed gears in the power flow path when fourth is selected, and the resulting drive ratio is 1:1. This results in five pairs of meshed gears: first, second, third, fifth and reverse. All five pairs are helically cut, and each pair is in constant mesh.

The five gears on the countershaft are a part of that shaft and, therefore, rotate continuously (driven by the input shaft). Their mating gears on the mainshaft are mounted on needle bearings, allowing them to rotate independently of the mainshaft until selected. The reverse idler gear is also bearing mounted, and its position on the idler shaft is fixed.

The transmission components are encased in a two-piece aluminum housing that splits vertically.

The shift lever, located in the passenger compartment, is linked to the control rod. This rod enters the top rear of the transmission housing and is able to select one of the three shift rods that are located inside the housing. Each shift rod has a shift fork attached to it, and this fork engages one of three hub sleeves. Gear engagement occurs when a shift fork slides a hub sleeve towards the selected gear. The toothed inside diameter of the hub sleeve then links the outside of the gear to the outside of the clutch hub. The clutch hub is fixed to the mainshaft with splines.

The clutch release lever and the crankshaft position sensor are located in the front housing. The back-up light switch is located in the rear cover on all models. The rear cover has an extension housing bolted to it. The vehicle speed sensor is mounted on the extension housing.