2002 4X4 not engaging quickly

I have a 02 Sequoia. 127000 miles not driven as much as I used to mostly on weekends. The 4x4 takes a long time to engage now. just stay blinking, i drive a little bit turn off car then hit 4x4 switch go into drive and sometimes 4x4 will engage. I know leave it in 4x4 in fear if i normalize car it will never go back into 4x4. is there something that needs to be oiled or lubed? I live in higher elevation there tend to be rust on metal in all of my cars due to elevation. seems to me something is sticking? in help is greatly appreciated. TIA