Sram Transmission compatibility

Riding friend is about to buy a new Trek Supercaliber. She’s a competitive adventure racer and doesn’t want the AXS derrailleur and shifter (7 day races, spares availability etc).

I’ve said I’d be happy to swap the GX mechanical parts from my Santa Cruz highball for her (and pay some $).

I’ve just seen that the Trek comes with Transmission though. Am I right in thinking that will only work with a UDH set up? I don’t think the Highball has that.

Transmission needs UDH. Not all UDH’s are compatible with Transmission though (but most are)

Thanks. Looks like the latest model has UDH but mine doesn’t…however it may be compatible.