99 2wd tahoe slip yoke issues

[slam59]

I have a 99 2 door 2wd Tahoe that is starting to have some issues again with the slip yoke. I have a friend at the local dealer ship who has taken it apart 2 times and greased it up to stop the clunking noise from a dead start and at slowing down that fixed it. The first time was about 6 months after I bought the Tahoe and about a year later it started again and he took it apart and greased it agin a second time. It has been about 5 years since the last time he did it and its starting again. I have been reading different forums via the google search and now see that many are replacing the slip yoke with a new nickel plated slip yoke and it has solved the problem. I think it might be a dealer only part as i try to look one up online and cant find one that states it is nickle plated.

My question is, why would a nickel plated one fix this? Is it because the grease stays on that type of coating and stays on the part better thus reducing it drying up? And if any of you have replaced yours with the nickle one, where did you get it and whats the cost? I am going to try and contact my friend in the morning and hope he still works there.