Trans dipstick

Just lift up the locking lever, if the dealer checked it last they should have put in a new red locking pin - that will break so they know you've been at it!

As with all automatics be very careful what you wipe the stick with.

Break the red tamper proof plug and pull the lever round and the cover will pull off. There's no dipstick there though, just the tube.

Auto gearbox dipstick is Merc special tool.