To find it:
1. Consult your owner's manual: This is the best place to start. It will show you a diagram of the engine compartment and pinpoint the dipstick location.
2. Look near the transmission: Open the hood and locate the transmission. It's a large, somewhat rectangular unit behind the engine. The dipstick will be somewhere nearby, often with a handle or a colored cap that's different from other engine components.
3. Check for markings: Look for a dipstick with markings indicating "ADD" or "FULL".
Important Note: If you cannot find the dipstick, do not attempt to add transmission fluid without confirming the correct location. Adding fluid to the wrong place could severely damage your vehicle. It's best to consult a repair manual specific to your van's year, model, and transmission type, or seek assistance from a qualified mechanic.