Dave, along with Pat Smear, Chris Shiflett, Rami Jaffee, Samantha Sidley and crew were visibly emotional after touching down. Dave hugged a man who looks like their manager, John Silva.

As we reported, Taylor was found dead in a hotel room Friday ... the group was in San Paulo to play Lollapalooza Sunday. Based on preliminary findings, it appears Taylor may have OD'd on 10 different drugs, including opioids.

Among the drugs in his system .... Tricyclic, antidepressants and benzodiazepines. An official cause of death has not been determined.

Less than a week before he died, Grohl told a massive crowd at Lollapalooza Argentina in Buenos Aires how incredible Taylor was ... best drummer in the biz, Dave bragged. He then had Taylor come center stage to both sing and show off his fly outfit.