Get Your Slush box Running Right
Today the automatic transmission is the drivetrain gear changer of choice for a lot of off-roaders. Choices are varied, and modern-built autos have proven to be durable and reliable.
An auto transmission uses fluid flow and pressure to transfer power from the engine to the drivetrain. A flex plate is bolted to the crankshaft at the rear of the engine and a torque converter is then bolted to the flex plate. Power is transmitted, via fluid coupling, from inside the torque converter to a splined input shaft on the automatic transmission.
The converter also serves as a torque multiplier (by a factor of 2 or more) as you accelerate from a standstill and allows the engine to idle in gear without moving. It also allows for smooth gear shifts and drivetrain slippage momentarily while gear changes are made, without affecting vehicle speed. In an auto tranny, the torque converter essentially takes the place of a clutch in a manual tranny.