James Kahn "World Enough, and Time" (1980).
World Enough, and Time is the first book of this spellbinding action adventure trilogy. In a post-apocalyptic world 200 years from now, humans are a dying species. When Joshua's wife is kidnapped by a griffin and a vampire, he and his comrades, a centaur and an android, set out to rescue her across a surreal landscape filled with seemingly mythological creatures. But the explanation for the existence of these beasts is based in science, and informed by nightmare. And the odyssey isn't over until they confront the evil cabal whose goal is nothing less than the extinction of the human race.
This was set decades after the collapse of society. A lot of different sub-species of gen-engineered people.
The hero was trekking through wasteland and for several chapters was accompanied by a 'Neuroman' female.
She was described as a semi-android person and she had caches of spinal lube fluid hidden all over the state - (I want to say she had a valve to fill up at the back of her neck)
Edit: Relevant extracts from the book...
*“I am the Doge of Venice,” he said. “You’ve come at a most inopportune time.
*On the very back of her head, a small valve was open, the size of a fingernail.
*Few have ever seen her, except for a small circle of ANGELS—Associate Neuroman Genetic Engineers, Lords, Sages.