Buick Enclave 2015 Owner's Manual page 347

11-6 Service and Maintenance
(3) Or every four years, whichever
comes first.
(4) Do not directly power wash the
transfer case output seals. High
pressure water can overcome the
seals and contaminate the transfer
case fluid. Contaminated fluid will
decrease the life of the transfer
case and should be replaced.
(5) Or every five years, whichever
comes first. See Cooling System on
page 10-12.
(6) Or every 10 years, whichever
comes first. Inspect for fraying,
excessive cracking, or damage;
replace, if needed.
(7) Or every 10 years, whichever
comes first.