I was planning on doing a drain and refill on the transmission in my wife's 2007 RX350 at 20,000 miles. When I thought it had T-IV fluid, I was going to use Amsoil Universal ATF, which is compatible. However, it turns out this transmission uses Toyota WS "lifetime" fluid. Apparently only Toyota ($42/gallon) and Redline ($11/quart) make compatible fluids.

How often should this be changed? I don't buy the whole "lifetime" argument, having just changed all such fluids in my BMW at 60k. And I know the RX is known for having tranny issues due to heat. So what is a good interval?

 

Honestly, i wouldnt worry about it at 20k miles. Ive changed it before at low milage, and it looks clean. Dont waste your money. Wait until at least 50k.

 

Lifetime fluid, don't waste your money!

Koz

 

Thats like saying Dexcool in GM vehicles lasts 150,000 miles...

in a controlled test environment, sure, but in the real world... it just doesn't last like that... contamination, excessive heat, excessive wear...

however, I do agree with RTGS, wait til at least 50-60k on that car... or just keep checking for fluid color changes...

I'm not saying the trans fluid doesn't last "forever" - but I am saying that if it doesn't you wanna be on top of it...

 

If you expect to sell or trade your RX before 150,000 miles then waiting until 50K miles to change the WS fluid will work out fine.

But if you desire to keep your RX troublefree for more miles then that then a partial fluid change (oil pan drain and refill) is a good idea at 20K to maintain the detergency of the fluid and to remove some of the suspended metallic particles in the fluid whichs in turn helps prevent the electronic shift control solenoids from malfunctioning due to particle buildup when the car has 150K miles or so.