No, they were not unified and there was a lot of infighting as various Christian kings and counts fought for control, particularly after the Cordoba Caliphate fell apart in the 11th century. There were some joint expeditions against the Moors, though - most famously, in 1212, when the combined troops of Castile, Aragon and Navarre soundly defeated the Almohads at Las Navas de Tolosa. Las Navas is considered the single most decisive battle of the Reconquista but in terms of intra-Christian co-operation this was more of an exception. Normally, what coordination there was was more along the lines of signing treaties to divide the yet-to-be-conquered lands between Castile and Aragon. Besides, Christian and Muslim polities would at times ally against other Christian and Muslim polities - see some examples I gave in my response to [this thread] (https://www.reddit.com/r/AskHistorians/comments/462233/what_were_islamic_iberias_relationships_with/d02y5c9).