10 Tahoe 6L80 with Cylinder Deactivation

[Speak2Mountain]

99.5K miles on clock, ATF never been changed. What to do? Drop pan and change filter and everything Pump and replace? No towing or off roading w/this ride. Thx

 

[mcrn]

I would drop pan.....replace filter.....then do drain and fills every oil change x 4.

 

[JHZR2]

Id pull what I could via dipstick, replace. Do this again maybe 500 miles later. Then do a pan drop with filter change. The logic is to get some fresh adds in there to loosen and disperse anything that may be ready to come off, and ensure that when you do the pan drop, since there was fluid in the TC, the remaining fluid will be a bit newer. Then the fresh fluid goes in.

 

[Speak2Mountain]

Thx guys, this is VERY interesting.

 

[oldoak2000]

Originally Posted By: Speak2Mountain

99.5K miles on clock, ATF never been changed. What to do? Drop pan and change filter and everything Pump and replace? No towing or off roading w/this ride. Thx

IF it's a 2010 factory fill was a full-syn fluid; 99.5k is nothing. Drain/drop pan; new filter, and re-fill with a quality full-syn Tfluid (MAXLIFE). Do again every 100k.