Yes, a replacement CSU is available for the 2016-2021 30 Gold TK/RL A1-A2.
11.4018.008.559 FORK CSU - SOLO AIR 29 51 OFF-SET ALUMINUM TAPER BLACK (NO GRADIENTS) FAST BLACK - 30 GOLD TK A1 (2014+)/RL A1 (2018+)/JUDY GOLD TK/RL A1+ (2018+)
RockShox service kits and spare parts are best obtained through your local shop or dealer. See our dealer locator, below, to find a dealer near you. If no one is currently listed near you, then please search for local shops via your preferred web browser.
https://www.sram.com/en/dealer-locator
Manuals and additional information about RockShox and SRAM components can be found at our service site, linked below.
https://www.sram.com/en/service
Further questions?
Reach out to Rider Support by Asking A Question at the link below.
https://www.sram.com/en/rockshox/campaigns/rockshox-rider-support