The grammar is the same but the Spanish pronunciation is different. Particularly the lisping "s" and in some regions they speak extremely fast. There are also words that are particular to Mexico and not used in Spain (chingado for instance).
This also applies to other latin American countries where each have their own vocabulary and particular expressions that are not used in other countries. In any case the basic language and grammar is the same but in latin America they are using a lot of english words that are not used in Spain.
If you want to unlearn Mexican go and spend some time in Spain.