Adjusting the parking brake: I'm pretty sure 108's have seperate shoes for park brakes, same as 116's independent of regular rear brakes. You dont just adjust the cable from underneath but look for screw-driver sized hole in back of PB drum for cam adjust that turns PB shoes closer to their drums. No dismantling required. Probly more DIY friendly as Tom suggested than messing with tranny linkages. If it was me thats what I'd do, or take it to skilled indie MB tech for pawl/drum repair.