driver321

I did a search and have come to the conclusion that Mobile 1 synthetic is now compatible with transmissions requiring type IV (Mobile 3309) fluid, but couldn't find the answer to this:

If I drain a 99 RX300 transmission, I won't be getting all the IV fluid out. Would it hurt to replace the drained fluid with Mobile synthetic, resulting in a mix of IV and synthetic fluid?

My plan is to have the fluid drained and refilled once every 30K, using synthetic each time, so eventually it would virutally all be synthetic.

I won't be doing the drain/fill this time due to my lack of time available to do it myself, so a transmission shop will do it for me.

Any thoughts on this?

lexus114

You should be fine,as long as it`s the latest formula.

driver321

Thanks for the reply!

lexus114

no problem,I was thinking of trying the new formula Mobil-1,or the latest formula Royal Purple max atf. (both a full synthetic) If your`s is AWD,you better change out the transfer,and rear diff. with synthetic.Makes a real nice difference....

Lexmex

I have done a drain and fill with Amsoil ATF and Type IV, I only noticed a positive improvement.

sktn77a

iTrader: (2)

Interesting that people can notice a difference swapping from traditional to synthetic fluids. I had all of my driveline fluids changed to synthetic a year-or-so ago and notice no difference whatsoever (?)

Maybe I'm just sensory deficient

lexus114

I wouldnt say that,the only difference i noticed was when I used the Royal Purple Max gear.Then I changed to Amsoil gear oil,and it feels like stock again.Im definitely going back to the RP Max gear soon. I know Ill get bashed for this,But I think Amsoil is overrated.