I have a 1985 K5 Blazer with a six inch lift and 33 inch tires. When I am driving it will make a strange chunking noise. Particularly when I am going up a hill or just starting out. It also happens when I am turning at slow speeds. It makes the noise in 4-wheel drive and 2-wheel drive. It seems like the noise is coming from right under the shifter that engages the 4-wheel drive. If anyone has any idea as to what it is please let me know. Thanks, TB2Blazer.