I've got a 1991 240. Having troubles with the shift lock release. When I first start car, I cannot press down button on the shifter - it's locked. So I have stick my hand down into the shift box to use the little yellow shift lock release in order to get shifter to move into position. If I drive around a while, park it, then come back and start it up, the shifter will move without problem. I've been told: it's some sort of valve; that I need a whole new gear box; or that there is nothing wrong with it. Of course, this last opinion comes after I've driven it to the shop and then it shifts fine. Any advice out there?