Torque converters since the 1980s include lockup clutches that lock the turbine to the converter shell to eliminate slippage. Which statement is correct?

Torque converters since the 1980s include lockup clutches that lock the turbine to the converter shell to eliminate slippage. Which statement is correct?

• A. Torque Converters Since the 1980s Include Lockup Clutches That Lock the Turbine to the Converter Shell to Eliminate Slippage
• B. Most Modern Commercial Vehicles Use Modulated Lockup for Increased Fuel Efficiency
• C. Both Statements Are Correct
• D. Neither Statement Is Correct

Answer: (A)

The main idea is that a lockup clutch in a torque converter eliminates slip by directly linking the turbine to the converter housing. Fluid torque converters inherently slip because power is transmitted through hydraulic fluid between the impeller and turbine. To improve efficiency, a lockup clutch was introduced around the 1980s to physically lock the turbine to the converter shell, so at cruising speeds the transmission can transfer torque without fluid slip, reducing wasted energy and heat. That straightforward improvement is why the statement about lockup clutches locking the turbine to the shell to eliminate slippage is correct. The other claim about most modern commercial vehicles using modulated lockup describes a more nuanced control approach to improve smoothness and efficiency, but it’s not the essential or universally applicable point being tested here.

The main idea is that a lockup clutch in a torque converter eliminates slip by directly linking the turbine to the converter housing. Fluid torque converters inherently slip because power is transmitted through hydraulic fluid between the impeller and turbine. To improve efficiency, a lockup clutch was introduced around the 1980s to physically lock the turbine to the converter shell, so at cruising speeds the transmission can transfer torque without fluid slip, reducing wasted energy and heat. That straightforward improvement is why the statement about lockup clutches locking the turbine to the shell to eliminate slippage is correct. The other claim about most modern commercial vehicles using modulated lockup describes a more nuanced control approach to improve smoothness and efficiency, but it’s not the essential or universally applicable point being tested here.