When the did the Attitude Era TRULY began?

I wouldn't say there was a specific event that really started it all, but I'd say it definitely began before Summer Slam 97. When they really started blurring the lines between heel in face, in the Austin/Hart feud, you were in the early stages of the era. In the traditional sense of old school wrestling, in that feud, Bret would be the face, and Austin the heel, but it was there, that the anti-hero Austin began to emerge, and things, that would made Bret loved prior, became the thing, that made him hated.
The Undertaker and Mankind feud that began in 1996 was another feud, that was also something that was part of the start of the Attitude Era. The Boiler Room Brawl at SummerSlam 96 was an Attitude Era type of match. And at that time you had Goldust around, another part of that era. The Austin/Hart fued, Taker/Mankind fued, Goldust character, the Austin 3:16 speech, those were all things, among others, that brought about the era. All things, that helped caused ripples towards the Attitude Era before SS97

It can be argued that the Attitude Era begin at KOTR 96 when Steve Austin gave his Austin 3:16 speech.

I have also heard it was around Wrestlemania 13 time, and even after Survivor Series.

for me....right around WrestleMania 13.

- you had audible cursing happening on purpose for the first ( "Frustrated isn't the goddamned word for it! This is bullsh^t!!!")

- good guys getting booed ( Bret, Rocky,etc).

- reintroduction of juicing.

- more violent matches becoming more common

- more weapons being used

- women really starting to wear risque outfits ( specifically Sable)

- conversion of Raw to "Raw is War", featuring an edgier style.

Bret's promo after losing the belt on Raw.

Kotr '96 imo. Austin's soeech didn't automatically start a new era but it was like lighting a fuse that eventually led to it.

Sid/HBK from survivor series might be the first case of this ever in wrestling.

I really cannot think of an instance that occured before that Survivor Series.

I believe the Attitude Era started between the time Monday Night RAW became RAW is WAR and Wrestlemania 13. Stuff like Austin's KOTR speech and Pillman has a gun were like seeds being planted to sprout the Attitude Era.

How in the world was Sid not a heel by Survivor Series..

He was a face when we won the title shot at Buried Alive as remained a face up to Survivor Series in my opinion. Yea he cut promos on Michaels and such but didn't have a full heel turn and was still facing other heels on Raw leading up to the ppv. I think they tried to turn him full heel at SvS by hitting Jose with the camera but it didn't take with the crowd. Even after Survivor Series he had supporters in his match with Bret Hart in December