I've done some searching and I've seen some issues resolved by running RP Syncromax in their NP246 transfer case in place of the OE Auto Trak II fluid. Have any of you done the same or would you recommend this? BTW, my truck is an '05 z71 with the L33 5.3 and 74K miles. I'm having some issues with the t-case, shifting in and out of 2WD, it's also making noise under 4WD. Thanks in advance.

 

This is the first Ive ever heard of this and have never seen it recommended.

 

It's funny, I actually PM'd you on another site as I saw you were having a similar transfer case issue a while back. I actually heard about Syncromax through a few threads during my research on the issues I was having. Even their website lists Syncromax as a replacement for Auto Trak II, "GM Transfer Case (PN12378508, PN12378396) Synchromax", http://www.royalpurple.com/transmission-chart.html (Just click the manual transmission link and scroll down to GM Transfer Case).

Anyhow, I ended up getting the Auto Trak II from the dealership and I tracked my issues down to a bad encoder motor / shift shaft bearings. Ordered up the new motor, and hopefully I should be good to go within the next few days.