Q: Hard shifting out of gear 1999 Chevrolet Tahoe

Hello - your symptoms suggest that either the shifter itself has stiffened up (needs grease and bushings?), or the shifter linkage inside the transmission has been damaged and is stiff. Disconnect the shifter cable at both ends, and try shifting with the shifter. If it’s still stiff, it’s something in the shifter that needs maintenance. Reconnect the cable to the shifter, leaving the cable disconnected at the transmission. Still moves easily? If not, cable routing may be a problem. If the shifter, with the cable moves easily, the problem is with the linkage inside the transmission. I recommend a transmission shifting problem inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.