I have a 97 Burb 5.7L K1500. It has a factory 3.42 gu6 g80 diff on the front and rear. My rear has rusted through the horizontal pipes, is leaking and I need to replace the entire read end. The only rear ends I see on craiglist are 3.73 gt4 g80. is this an option? Will the gt4 fit seamlessly? Can i damage my vehicle if I use 4wd with diff ratios?