By the same token the burden of proof is on you to show that changing trans oil in the 6-speed prolongs life. Yes lab tests have been done showing oil contents, but that doesn't translate to failed transmissions. Show me one instance where someone's LS 430's transmission failed due not changing the oil. By the same respect, I can show several instances ( like this thread) where problems arose due to tampering (albet it incorrect oil levels) resulting in hard shift, slipping etc. 300,000 miles is still in the future so until someone has reached that mileage you nor I can attest either way.

 

I'm not going to argue with you. Drink the Kool-Aid if you want. Aisin, the manufacturer, has always recommended changing the fluid. Lexus says you should change the fluid in every other part of the world besides the United States. Owning a LS400 for some years I am also very familiar with how well the Aisin transmission will last if properly serviced. People who don't service the transmission will usually loose it between 200k and 300k. Those who take care of it have gone over 500k miles on the same gear box. Lexus services my transmission and recommends the drain and refill every 60k.

Also, it's the metal content and the break down the the additives in the WS fluid that the lab test clearly demonstrate. The clutch pack additives are extremely important to the performance of the transmission. Of course there is some risk to servicing any component. If done improperly you run the risk of failure. This is why I have Lexus do the service.

 

I agree with you but sometimes people just like to troll different forums. If people think you don't have to change your vehicles fluids, then they really are pretty slow, if you get my drift... LOL.

 

I'm gonna bump this from the dead...Do you do your trans drain and fill cold? Reason I ask is because I have access to a lift but I have to drive to get there. By the time I get there the trans is warmed up and volume of the fluid drained will be different (not sure by how much) compared to the fluid being filled because of the temp difference. So I wouldn't be able to get the exact volume replaced.

 

The volumetric change due to temperature is insignificant, don't worry aobut it.

 

agree with that. On the other hand, I've always drained after a good long drive, on the assumption that heated fluid would flow better, and therefore you'd get more out. I have no real data to support that assumption however.

 

Level car and topping off the ATF fluid once ATF fluid temperature reaching operating temperature is what you ought to focus on. After all, your current fluid level may be low. The LS430 ATF level check is done after fluid reaching operating temperature NOT cold. Warmer fluid helps the fluid to drain quicker, like motor oil. The warmer fluid will actually be slightly higher than a cold fluid level.

 

If you measure the ATF fluid that was drained out after it has cooled down you can ignore any volumetric expansion based on hot fluid drain and put back in the exact same amount of new fluid based on measurement of cooled fluid.

 

Check the directions in the main thread, heating the transmission to the proper temp after you refill is the best procedure. This allows you to double check the fluid level. It has happened with others on the forums who have not properly refilled the transmission because it would not take the proper amount of fluid all at once. Heat until proper temp, run it through the gears once or twice and check level again before you finish and put the covers back on. Remember to disable the air suspension if you have it and your engine is on with the wheels off the ground. Pull the fuse for the compressor.