I only experience this during cold starts in the morning.

I notice that pag engage ko sa reverse after initial startup, biglang magrerev ang engine causing it to "thud" reverse.

I don't experience it after the engine is warmed up specially when AC is on.

Ano kaya ang problem? Sabi nila yung "thud" experience might be due to worn out engine support?]

Car btw is an Altis '03 AT

TIA.