Most folks on this forum recommend changing the AT fluid every 15-20k miles. The Lexus owners manual states that under normal driving conditions, the AT fluid does not need to be changed. I have an 02 RX300 FWD with 113k miles. It drives like it did when it was new. Should I go ahead and change the fluid to be safe?

Also, regarding the engine sludge issue, what is the recommended motor oil? Synthetic? Conventional? I've been using Castrol gtx 5w-30 every 3k miles.

 

Personally I would use full synthetic of your choice...good weight is 5-20, but I used Castrol oil 0-30 and when I sold my RX300 after 188k miles and 12 years it still ran like a top. As for the tranny fluid it is not lifetime...Change once a year or every 20k miles and your car will love you...do not do a flush, drain and fill only. You could stretch your oil changes safely to 5k with the synthetic....

 

With the ATF fluid, I also strongly suggest you change it to a full synthetic ATF (there's many out there such as Amsoil, Redline, Royal Purple, Mobil 1, Wolf's Head, Eneos) that are type IV compatible.

On oil, with Castrol 0W30, I have been running 7500 miles until changeout.

 

Just did a fluid exchange using Wolf's Head super universal and it is shifting great. Thanks to all in this for

 

Good stuff!! Thats what I used in my 01. Worked great!

 

Good stuff too! You shouldnt have any problems with that oil. I know everybody is on the "Synthetic" band wagon. Synthetic only really shines on long drain intervals, (which most vehicles are not set up for) unless your talking the vehicle being set up from the factory for it. I.E Mercedes-Benz, holds around 8qts of oil, fleece oil filter. These cars are designed for long drain intervals, most RX`s are not. Except for maybe the new ones. All you need is a good Conventional oil GTX,Pennzoil,Valvoline etc,change every 3k,and you will be good to go. And unless your motor was neglected, will way out last the rest of the vehicle. Especially the transmission. I like using Synthetic oil in the transmission of the early RX`s due to the failure rate. I use Type IV in my 05, the only thing I have Synthetic oil in right now is the transfer,and rear diff. Only because I dont want to have to change it as often.

 

I've been using 10K mile change intervals on my wife's '02 AWD since about 40K miles, and while it has only 95K miles on it, the next oil change, I'm going to drop the pan to see what it looks like in there. This is curiosity more than anything.

I did try one 15K mile change, but I think it was borderline too long. Changing @ 10K, it requires no additions. It was about 1/2 quart low at 12K miles, though, so I added. I considered doing testing, but I know the car will long outlast my wife's desire to own it, even though I told her when she got it in '04, it's the last car she'll ever have.

I really wish there were a larger oil pan available for this engine. 7-8 quarts is routine for MB on gasoline engines this size, and I'm convinced this is a huge contributor to long engine life. The new-to-me '05 STS V8 holds 8 quarts, and is synthetic from the factory. The oil life indicator looks like it'll give me about 12K miles between changes.

Transmission...I go to the Toyota dealer and get a case at a time, change it every 30K. The car doesn't sit in traffic, much, so this is most likely just fine. We do live in a rather warm climate, however...Vegas wasn't any better.

Engine oil. Even on dead dino juice, 5K should be plenty often.