hey guys, sorry to hear about your woes. i had the same problem on my sprinter. its caused by the relay that controls the hydraulic pump for changing gears. bosch superceeded the relay as it wasn't up to the job. on mine however i found out the hard way and have had my hydraulic pump replaced twice. the relay tends to make the pump pack up. it sounds like this has happened to both of your vehicles too. you might get away with just changing the relay, but i'd say your pump has had it too, sorry.
happymick13, November 2008