- 2025–2027 Factory-verified
only in: 2500 HD; AT4, Denali, Denali Ultimate: O; Pro, SLE, SLT, AT4X: not offered
RN6 Factory-verified
Also documented for Chevrolet
Documented applications
This page aggregates every documented appearance of RN6 in the GMC reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.