AUDI Transmission & Drivetrain Systems 2 — Questions and Answers
Question 1: When replacing an Audi S tronic mechatronic unit, what must be completed after installation to ensure correct operation?
- Only an oil fill-level check is required
- A basic settings procedure and clutch adaptation via ODIS (Correct answer)
- A static wheel alignment and throttle body adaptation
- A power steering bleeding procedure
Correct answer: A basic settings procedure and clutch adaptation via ODIS
After installing a new mechatronic unit, ODIS must be used to perform basic settings and clutch adaptation so the new unit learns the clutch kiss-points and selector fork positions.
Question 2: In Audi's quattro ultra system (found on some A4/A5 models), how does torque distribution to the rear axle differ from classic quattro?
- It uses a Torsen differential that is always engaged
- It can fully disconnect the rear axle when AWD is not needed to save fuel (Correct answer)
- It locks the center differential for better off-road capability
- It uses a belt-driven secondary output for the rear axle
Correct answer: It can fully disconnect the rear axle when AWD is not needed to save fuel
Quattro ultra uses clutch systems on the prop shaft and rear differential that can fully decouple the rear axle during light-load cruising, improving fuel economy compared to always-engaged quattro.
Question 3: What does a worn or failing CV (constant velocity) joint on an Audi driveshaft typically sound like when turning at low speed?
- A low-frequency rumble during straight-line acceleration
- A clicking or popping noise during tight turns (Correct answer)
- A high-pitched whistle from the wheel bearing
- A grinding noise only during braking
Correct answer: A clicking or popping noise during tight turns
A worn CV joint produces a characteristic clicking or popping sound when the joint is operating at a steep angle, such as during a tight turn, due to worn ball bearings or races.
Question 4: On an Audi with a 7-speed S tronic, gear 'K2' refers to which clutch pack?
- The clutch engaging 1st, 3rd, 5th, and 7th gears
- The clutch engaging 2nd, 4th, and 6th gears (Correct answer)
- The reverse gear lockout clutch
- The torque converter bypass clutch
Correct answer: The clutch engaging 2nd, 4th, and 6th gears
In the DL501 7-speed S tronic, K2 is the 'wet' clutch pack that drives even-numbered gears (2nd, 4th, 6th), while K1 drives odd-numbered gears (1st, 3rd, 5th, 7th) and reverse.
Question 5: What is the correct procedure for checking the fluid level in an Audi S tronic transmission?
- Check the dipstick with the engine cold before starting
- Run the transmission to operating temperature, then check via the overflow/filler plug at the specified temperature range (Correct answer)
- Remove the drain plug and measure the outflow volume
- Check via the reservoir sight glass at the top of the transmission
Correct answer: Run the transmission to operating temperature, then check via the overflow/filler plug at the specified temperature range
S tronic fluid level is checked via the overflow method: the transmission must be at the specified temperature (typically 35–45°C), the filler plug removed, and fluid is correct if it just trickles from the hole.
Question 6: Which ODIS function should a technician run if an Audi with S tronic exhibits harsh shifts after transmission overhaul?
- Injection quantity adaptation
- S tronic basic settings and clutch kiss-point adaptation (Correct answer)
- ABS sensor calibration
- Throttle position sensor relearn
Correct answer: S tronic basic settings and clutch kiss-point adaptation
Harsh shifts after overhaul are typically caused by incorrect clutch kiss-point data; running S tronic basic settings and clutch adaptation in ODIS resets this data so the TCM can relearn proper engagement.
Question 7: In Audi's longitudinal quattro drivetrain, what is the purpose of the rear differential's electronic differential lock (EDL)?
- It physically locks the rear axle shafts together for off-road use
- It uses brake intervention on spinning wheels to simulate a limited-slip effect (Correct answer)
- It disconnects the rear axle when understeer is detected
- It prevents torque from being sent to the front axle
Correct answer: It uses brake intervention on spinning wheels to simulate a limited-slip effect
EDL (Electronic Differential Lock) uses the ABS/ESC system to apply braking force to a spinning wheel, transferring effective drive torque to the wheel with more traction without a mechanical locking diff.
AUDI Transmission & Drivetrain Systems 2
When replacing an Audi S tronic mechatronic unit, what must be completed after installation to ensure correct operation?