Guardado will join Leverkusen on a temporary basis until June before the German outfit makes the decision to bring him to the BayArena for good.
Pabon, 26, who only moved to the Mestalla in August from Mexican outfit Monterrey, has joined the Brazilian club on a permanent basis until June 2015.
Meanwhile, Postiga has sealed a loan deal with Edy Reja's side until the end of the season, with the Biancocelesti having the option to make the move permanent in the summer.
Both the Mexican and the Portuguese will travel to their new clubs for the formal completion of medical procedures before the deals are finalized.
Valencia is enduring a disappointing season in La Liga, with Juan Antonio Pizzi's side currently in 10th, 17 points off the Champions League places.
- Sports & Recreation
- Bayer Leverkusen
- Andres Guardado
- Helder Postiga
- Dorlan Pabon