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2018 A4 Allroad S-Tronic Hesitation and Rough Shifts

0

Mike T. · rep 0 · May 26, 3:42 AM · 1 replies · solved · Question

Vehicle: 2018 Audi A4 Allroad Prestige

Hey everyone,

I've been experiencing some really frustrating issues with the S-Tronic transmission in my 2018 Audi A4 Allroad Prestige. It seems to hesitate quite a bit when accelerating from a stop, almost like it's unsure which gear to pick. This is especially noticeable in stop-and-go traffic.

Beyond the hesitation, I'm also getting some rough shifts, particularly between 1st and 2nd gear, and sometimes 2nd to 3rd. It's not a smooth transition like it used to be. The car has about 65,000 miles on it, and I've kept up with all the recommended services.

Has anyone else with a B9 A4 Allroad experienced similar transmission behavior? What was the fix? I'm hoping it's not a major issue.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 26, 3:42 AM

0

ClearTheCode admin answer:

Transmission hesitation and rough shifts in the Audi S-Tronic (DSG) are not uncommon, especially as vehicles accumulate mileage. Here's a breakdown of potential causes and what steps to take:

  1. Software Adaptation/Updates:

    • Cause: The transmission control unit (TCU) learns your driving style. Sometimes, this adaptation can become 'confused' or benefit from a factory reset. Additionally, Audi occasionally releases software updates that address known shifting issues or refine the transmission's behavior.
    • Action: A dealership or an Audi-specialized independent shop can check for and apply any available TCU software updates or perform a basic settings adaptation.

  2. Mechatronics Unit Failure:

    • Cause: This is a common failure point in S-Tronic transmissions. The mechatronics unit is the brain of the DSG, combining the TCU with hydraulic solenoids and valves that control the clutch packs and gear selection. Internal pressure leaks or solenoid failures can lead to erratic shifting, hesitation, and even complete transmission failure.
    • Action: Diagnosis via VCDS or ODIS will often reveal specific fault codes related to the mechatronics unit (e.g., P17D8, P17D4). Replacement of the mechatronics unit is a significant repair.

  3. Clutch Pack Wear:

    • Cause: Like any clutch, the wet clutch packs in the S-Tronic can wear over time, especially with aggressive driving or heavy traffic. Worn clutches can lead to slippage, hesitation, and harsh engagement.
    • Action: This is typically diagnosed by monitoring clutch slip values and observing transmission behavior. Replacing clutch packs is a labor-intensive and costly repair.

  4. Transmission Fluid and Filter Service:

    • Cause: While you mentioned keeping up with service, ensure the S-Tronic fluid and filter service (typically every 40,000 miles) has been performed with the correct fluid. Old or contaminated fluid can impair shifting performance.
    • Action: If overdue, perform the service. Even if done, ensuring the correct fluid and fill level is crucial.

When to See a Shop: Given the nature of transmission issues, it's highly recommended to have your 2018 Audi A4 Allroad inspected by an Audi dealership or a reputable independent European car specialist as soon as possible. They have the specialized diagnostic tools (VCDS/ODIS) to read transmission fault codes and perform specific tests to pinpoint the exact cause. Delaying diagnosis and repair can lead to more severe and costly damage.

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