GSteg

iTrader: (15)

That's dealer talk. Amsoil is approved for Type T-IV replacement. It wasn't until recently that they got licensed for it.

My local lexus dealer told me the same thing. i asked them if I could use Mobil 3309 ATF. They said absolutely not because my transmission will fail. Which is stupid because Toyota Type T-IV is rebranded 3309. I wouldn't trust a dealer verbally. Take what he/she said, then research to see if its true.

McKrevice

iTrader: (1)

I flushed my tranny fluid with Toyota brand, and it seems to shift a bit harder than before. Nothing bad, but noticable, not silky smooth....so I was thinking of switching to Amsoil...I have heard good things about it. What's the type I should look at?

Mr Johnson

Go with the synthetic and stick with the lower weight oil. Assuming you are in mid to northern Indiana you will get plenty cold and running 20W rather than 5W would do more harm than good, IMO.

FWIW: I've run 5W30 Synthetic (Royal Purple and Mobil 1) for 7 winters now. Life is good.

Rock-a-Lex

iTrader: (4)

Is Mobil 1 a really good synthetic? I have a 2000 GS400 w/103K on her and for the LONGEST time I wanted to switch to synthetic. Maybe I'll do it next time...but I'm still scared.

vrferrari

I run Mobil 1 Synthetic 5W 30 in my GS4 year round in Phoenix AZ.
I would submit that because of the lower viscosity of the 5W oils, regardless of the lubrication factor, would allow more lifter noise to be heard from the engine simply because of the less affect of the dampnening of noise that a lower viscosity (thinner) liquid would have versus a heavier (thicker) fluid.

vrferrari

oh.....and I have 143K+ miles on my ride and still going strong.