I had my car in the air the other day, and noticed that the differential seemed to be leaking from nearly every seal. I generally know my way around the engine, but I'm very green with respect to the differential/drivetrain. I have access to a lift and the necessary tools, but don't know what seals/o-rings I should order and replace...all of them? According to the CD set that I have (Model 124 Service Manual Library), it mentions that I should also replace all of the 'collared' bolts. Is that necessary? ...or just a good suggestion? I can't find those bolts on-line anywhere.

Any input would be greatly appreciated! Thanks in advance!