The rift between Sunni and Shia was origionally political.If all hadith are based on the Quran, why the differences in what is accepted between Sunni and Shia?
A division between two camps over who was going to lead after the death of the Prophet.
Both believe in the Quran exactly as written.
But the Hadith, which is made from thousands of sayings of Muhammad.
Was cherry picked, mainly by the Shia, to support their version of Islam.
Which in turn, supported their political claim to religious rule.
Hope this helps.