auto trans dip stick

On an ’84 300SD, I wouldn’t force it yet. There is supposed to be a locking lever on that cap. The black piece underneath the red cap swings up and releases the clamp around the dipstick tube. Once that lever is released, the cap and dipstick should come out.

If that little lever is missing or broken, that may be exactly why you’re stuck. I’d look closely underneath the cap and see if there’s a small black hinged piece you can get a finger under. Don’t put a pair of pliers on the cap and start twisting it yet; it’s old plastic and you’ll probably just make the job more expensive.

There are replacement locking caps available, and Mercedes owners have been replacing these for years.

One other thing: once you get it out, check the end of the dipstick. These old Mercedes sticks can have the rounded end broken off, which can make the level markings misleading.