[ppyzyna]

You could send a sample to Blackstone Labs and get a report on it. I am due to change mine and I already have the WS Toyota oil and a Wix 'filter'. ( I am in a 'no salt' zone and have been spraying PB-Blaster on pan bolts, they look okay.). I am planning to send a sample for analysis.

 

[ppyzyna]

One positive thing about dropping the pan is that you can see what has accumulated on the magnets and bottom of pan. Also, if you have considered a shift-kit, you would need to drop the pan. That pump-out method described sounds like the best way to go to get a thorough ATF change.

 

[ppyzyna]

But if you are in town driving, towing heavy and hard, off-roading, etc, you should change your fluid more often and consider a full fluid change instead of just replacing what is in the pan.

I will prefer to do the change myself... However, I have some prepaid Oil Sample kits from Blackstone Labs, so as soon as I can I will suction out a sample thru the fill plug opening, (only a few ounces) and see what the report says first. I would intend to do a complete change of fluid, either myself or by the local dealer.

 

[ppyzyna]

Anyway, I am wondering how the transmission, being "sealed', handles the change in internal pressure due to expansion and contraction of the trans fluid. I could not find an answer in my research. I would think it would need some sort of expansion tank. Everything else filled with oil in the drivetrain has a breather fitting of some kind.