If your vehicle is showing loud clunk when shifting from park to drive, here are the most likely causes and the parts you'll need to fix each one.
On rear-wheel or four-wheel drive vehicles, worn U-joints develop excessive play. When the transmission engages, this slack is taken up instantly, causing a loud metallic clunk.
Rubber mounts secure the powertrain to the chassis. When they tear or collapse, the torque of shifting into Drive causes the entire engine and transmission assembly to physically jump and slam against the frame.
On front-wheel or all-wheel drive vehicles, worn inner CV joints develop internal slack. Shifting into gear forcefully takes up this slack, resulting in a noticeable clunking noise.
The driveshaft slip yoke can bind on the transmission output shaft due to a lack of lubrication. When torque is applied during a shift, it suddenly breaks free with a clunk or thump.
If the engine is idling too fast due to a faulty idle air control valve or vacuum leak, the transmission will engage with too much force, causing a harsh shift and clunk.
A failing electronic pressure control solenoid or sticking valve body can cause the transmission to default to maximum line pressure, resulting in a violent slam into gear.