2High light goes out on 4wd with service 4wd message

gmc
yukon

#1

I have a 2005 GMC Yukon 4wd w/90,000 plus miles. The 4wd was serviced at 60,000 and ever since the “service 4wd” computer alert keeps coming on the dash in no regular interval, but more frequently. Also the 2 High light goes out and often will not come back on for a short time. Any ideas?