Code reader comes up PO0700 and P00731. Some slipage noted. Higher RPMs when driving and idling
You don’t say how many miles are on your van but you’re probably at least due to have the transmission fluid changed if not past due. Check the fluid if your vehicle has a transmission dipstick and take it to a good independent transmission shop. A fluid change might allow you to dodge a bullet.
Those are transmission codes. A fluid and filter change MAY help. Be sure they add ATF+4 fluid only.