Is there a transmission leak preventer that's ok to use?

[jbach36]

A year ago when I bought my 1991 300d, the power steering pump was leaking, a common problem for Mercedes. I was surprised (and delighted) to find a power steering leak stop that wouldn't hurt the seals. The old stuff would puff the seals temporarily, then you ended up with a real problem when the stuff wore off. The new stuff I got, they said it simply rejouvenates the rubber seals. I've had it in for over a year, and it's certainly helped.

Has anyone tried anything like this for their transmission? And/or, how hard is putting in a new seal for a transmission? I'm sure it's not a DIY project.

Thanks,

Jeff 1991 300d, 111k