Difficult? Not really. Dirty? Yes. Some very cramped spaces? Yes. See my post -- perhaps search on hair and gojo. Improvement? Wow! My W124 '92 TE is so lovely now. Go ahead and change your fluid while you are at it. I didn't, and wish I had. Almost half comes out to do the job anyway.
1986 300E Anthracite + ECodes + MB Mileage Award