1998 Toyota Sienna XLE

Getting vibration when stopped, more in drive than neutral. Also, when backing, especially with a turn, I often get a “clunk”.

in the wheel or seat?

stick or auto?

The vibration is coming from the engine. Most of the noise comes from the dashboard rattle (plastic on plastic where two parts of the dash are joined).

automatic transmission

The engine is vibrating because it needs a tuneup (routine maintenance). Change the usual maintenance items: spark plugs and wires, air filter, fuel filter, etc.