Rb8?
No @IanMeows. Sorry. Yes @hbpencil1 - you are right this time too.
i bet u looked at analysis
34.Rb8 loses the rook for nothing. The straightforward 34.Rb7 seems to win easily enough. If there's a winning combination, I couldn't find it.
1.a6 Bg5 2.Qb7 Qxb7 3.axb7 Rb8 and white is winning.