Is replacing the seals in a steering box, W140 in this case, a straightforward task or does it require special tools and precision measurements? The bottom of the SD steering box is a little wet. Wondering if I should try to reseal it or let it get worse then replace it. Steering and tracking feel fine.

To put it in perspective, I can replace a head gasket but I don't have the skill or knowledge to work on a differential.

Thanks,
Sixto
93 300SD