Tranmission Fluid flush and filter change

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Shipyard

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Yesterday I just did just a first flush on a 2016 with 6L80 at 50k miles. I used method where the transmission’s pump does the work using the return line and Hayden 397 fitting/hose. About 14 qts resulted in much cleaner fluid cycling through. I plan to flush again at 75k miles and again with a filter change at around 100k.

Theres lots of videos and threads out there for a DIY flush, but one confusing thing for this year/model (2016 with 6L80 without towing package or aux cooler) was figuring out what line/fitting on the trucks trans cooling system to use… some hook up at the thermostat. For mine, the return line fitting is in a tight spot on the drivers side on the bottom of the radiator. Also the line needs to come off the close-by hanger as it’s pulled out of the female fitting.

Also… With mine warmed up to 180, I didn’t have any fluid pumping out of the pulled off line (because of the thermostat) in addition to the discharge hose. I did have a hose on that line too though, just in case.
 

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Bob2C

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Yesterday I just did just a first flush on a 2016 with 6L80 at 50k miles. I used method where the transmission’s pump does the work using the return line and Hayden 397 fitting/hose. About 14 qts resulted in much cleaner fluid cycling through. I plan to flush again at 75k miles and again with a filter change at around 100k.

Theres lots of videos and threads out there for a DIY flush, but one confusing thing for this year/model (2016 with 6L80 without towing package or aux cooler) was figuring out what line/fitting on the trucks trans cooling system to use… some hook up at the thermostat. For mine, the return line fitting is in a tight spot on the drivers side on the bottom of the radiator. Also the line needs to come off the close-by hanger as it’s pulled out of the female fitting.

Also… With mine warmed up to 180, I didn’t have any fluid pumping out of the pulled off line (because of the thermostat) in addition to the discharge hose. I did have a hose on that line too though, just in case.
You should change your thermostat as well. Mine runs about 150 max 160. It’s an easy job
 

Shipyard

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You should change your thermostat as well. Mine runs about 150 max 160. It’s an easy job
Mine normally runs cooler like yours does . I wanted to be certain the temp was up so it would pump through the return line… so I drove it harder than normal for the 15 minutes before getting home. Towing a 4500 lb trailer in the summer, it didn’t get over about 195 if I remember right.
 

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