ChevyDude123

I’ve searched previous forums and haven’t found the feedback I’m looking for, although this is a common topic. So bear with me. I have a 1999 Silverado 1500... 5.3L.... 4l60e... 4WD... NP246 TC.... 3.73 gear ratio... 160k miles. The symptoms I’m having are namely: Large clunk when shifting into reverse. A less noticeable, but still at times, a clunk when shifting into Drive. Harsh down shifts when coming to a stop from cruising speeds. Today, I put the truck on 4 jack stands so I could get a better idea of what is going on. After being under the truck during shifts between Park Drive and Reverse , it seems to me the “clanking” is originating from the Transfer Case. And mainly from the output shaft that drives the front diff. When the truck is turned off and in park, I can manually with my hands rotate the front drive shaft back and forth and replicate the same (ish) banging noise I hear when making those shifts between P D and R. The noise is consistent whether the truck is in 2WD, 4 HI, or 4LO. I guess my question in general is what testing can I do to further look into this and figure out the root cause? Would these symptoms typically originate from the tcase? My long term plan is hopefully to replace both the Transfer case and front diff with either low mile junk yard OR remanufactured units. after replacing those things, assuming a good install, do you believe the “clanking” will be fixed? In general, the truck is shifting through gears like dog ******. But I love her and want to renew it over time.