Why is there a noise when shifting gears in an automatic transmission?

[Nettie]

Automatic transmission gear shifting noise reasons are as follows: 1. Not stopping completely when shifting: When parking, the car should be completely stopped before shifting the gear lever from D to P. If the car is not completely stopped when shifting to P, the P lock hook inside the transmission will hit the gear and make a clunking sound. This operation will cause the lock hook to wear or even break, and in severe cases, it can lead to transmission failure. 2. Incorrect operation sequence when parking on a slope: For automatic transmission models, the P gear relies on the lock hook to hold the gear in place to achieve stability. When parking on a slope, the handbrake should be applied first before shifting to P, so that the handbrake bears the vehicle's sliding force. If P is engaged first and then the handbrake is applied, the vehicle's sliding force will be entirely borne by the P lock hook, keeping the lock hook and gear tight, which will cause a noise when shifting from P to other gears.