I need some help. I have a 99 Tahoe and it is making this clunking noise whenever I accelerate from a complete stop. I have been reading about a lot of similar problems on here. Mostly all of the problems are the same thing, the “slip yoke”. I am going to perform a transfer case flush and grease up the slip yoke to take care of the problem, but I was wondering if anyone can recommend a good oil for the transfer case and grease for the slip yoke? I tried to look for the “Auto Trac II” oil but was unable to locate it in any of our part stores. If anyone knows how to order it online, please can you give me the web site, If not, can you please recommend another type of oil. :)

Auto Trak II is AC Delco Part Number 10-4017. You should be able to find it at any AC Delco Parts Store (see http://www.acdelco.com/index.html).

It is also available at Dealers under Part # 88900402

//2000CAYukon

Thanks for the info. We don't have an AC Delco here but I will check out the web site or try a dealership here. Thanks again....