When I fully compress the rear shock, the rebound appears to be undampened for the first 80% of the return travel, then is dampened for the last 20% of travel.

Is it low on oil/N2? Service or replace it?

Servicing is for sure cheaper. There`re used ones for sale once in a while but one never knows their real condition.
If you decide to service yours take a close look at the damper rod. If the chrome is chipped or damaged that maybe the reason why an oil seal leaked. Over the time you`ll also notice that the swingarm linkage is oily.
I had that on my first shock so I took it to the main Marzocchi importer. They told me I`d need to replace it as it was impossible to find a spare damper rod. According to them polishing or rechroming was no durable solution.
So it would be important to find out why the shock doesn`t work properly anymore, if due to a damage or just as a matter of age.

G.

Ok, I do understand the need for an undamaged shaft.

What affect does the N2 charge perform? Could this cure my rebound problem?

Is it possible to perform a "leakdown" test on the unit to verify the seals/o-rings are bad?

Can I add oil myself somewhere?

Do we have a manual for the specific unit used on our bikes?

I'm asking because whenever I go to a shop around here without some idea of what to expect, they flat out screw me.

Help!

The shop that is rebuilding the shock can't find replacement seals or seal head.

Does anyone know where to source these parts or have a cross referenced part from another vendor? Its a 14mm ID with a 40mm OD. My seal head has the hex head to accept a wrench rather than two holes for a pin driver.

Thanks!

these two shops list the complete rebuild kit. They do list every part number so one needs to ask about availability.
http://www.store.commoto.com/ducatistor ... 76960.html
http://store.proitalia.com/ducati-oem-s ... 18422.html

Have you checked at a Ducati dealer with the part number (36640011A) ?

G.