XT5 dark trans fluid drained at 31k mi

[nascarnation]

Not too many folks here are doing oil analysis on ATF and it's been 18 years since I did any at work, but I'd expect Dex VI to be good for 100,000 miles if the typical operating temp was 220f.
I can't comment on the color other than there are posts about transmission fluid turning dark from anti-rust coatings applied to the internal components for storage/transmissionit at the factory.
If you're really concerned, put in something that meets Allison TES-668 and you'll be in great shape.

 

[MurkyAsparagus]

For everyone here wondering about changing out the filter; these 9Txx transmissions do not have a serviceable filter, the filter is internal to the transmission casing.

9T50 is practically the same as the 9T60 I have in my '23 Blazer. I plan on a service every 25-30k miles using Dexron VI full synthetic transmission fluid. It's an extremely simple process to do a drain and fill, only need a new drain plug which is readily available from RockAuto. I see some use a Votex magnetic drain plug.

I've looked around and don't see many failures before ~100k miles or so. Those that post failures often say the transmission was never serviced. The key to these transmission is clean fluid changed early and often.

 

[martinq]

For everyone here wondering about changing out the filter; these 9Txx transmissions do not have a serviceable filter, the filter is internal to the transmission casing.

9T50 is practically the same as the 9T60 I have in my '23 Blazer. I plan on a service every 25-30k miles using Dexron VI full synthetic transmission fluid. It's an extremely simple process to do a drain and fill, only need a new drain plug which is readily available from RockAuto. I see some use a Votex magnetic drain plug.

I've looked around and don't see many failures before ~100k miles or so. Those that post failures often say the transmission was never serviced. The key to these transmission is clean fluid changed early and often.

Any "good" magnets in the system will do more productive filtering than a typical full-flow filter will. At the very least I would recommend a magnetic drain plug and an inline magnetic filter like the one some Honda's use or the Magnefine.