2021 Volvo XC40 T2 | 1.5L 3-Cylinder Petrol | Mileage: 57k KM

The Issue: Cold Start "Knock" (Aisin 8-Speed)

I need a second opinion on a specific mechanical noise coming from my car. Maybe transmission related: Aisin AWF8F35.

It only happens when the car is not used for 8-10hours. After 1-2min usage it’s perfectly smooth.

The Symptoms:

• The Knocking Sound: On a cold start, I get a distinct "knock" during the first 2nd-to-3rd gear upshift. It happens exactly once.
• Stationary Knock: If I shift into Reverse while stationary (cold), the same knock occurs immediately.
• The Disappearing Act: After the first few minutes of driving, the sound completely vanishes.

Work Done So Far:

1. Official Dealer: Flushed transmission oil and performed a software adaptation reset. No improvement. Their verdict: Replace the entire transmission. :)
2. Transmission Specialist: Found the dealer’s replaced oil was dirty and under-filled. Flushed it again, refilled to spec, and performed another adaptation reset.
3. Result: A bit quieter, but still there every morning. No error codes.

Has anyone seen this "one-and-done" behavior on these Volvo XC40 and Aisin units? Trying to avoid a total swap if it’s a peripheral part.