There isn't anything really special about the T-IV, as opposed to the WS which is much thinner than anything aftermarket. I've heard a lot of long-term positive experiences with people using both M1 and Amsoil universal synthetics over at BITOG, and recently Castrol has a Import ATF for T-IV and Honda's Z1 which some people have started using and seem to like but hasn't been around long enough to give a definitive thumbs up.
At 40,000 miles I did a 4 quart drain/fill with T-IV, and at 60,000 I'll be doing the same thing with M1 and transitioning to that over the next few OCI's. The M1 cost less and is a better oil than the T-IV (also made by Mobil). Whether or not the M1's friction characteristics are similar to T-IV only one group knows for sure, Mobil employees, and they have M1 ATF recommended for replacement for about two years now.
To be honest, just changing it with either puts you way ahead, and T-IV isn't very expensive (about 4 bucks a quart at my dealer).
Of course, now for the barrage of people who know you can never be wrong writing a post saying to stick with OEM.... If anyone actually has a negative experience using a substitute for T-IV, I'd love to hear it.
Amsoil is a good post-warranty ATF. T-IV is what I will stick with until warranty.
I flushed out T-IV and put in Amsoil while in warranty only to learn that Toyota has a marker on the fluid. If I had a transmission issue, they will dishonor the warranty. Put back T-IV to be safe and put the Amsoil into my other vehicle.
BTW, I did a drain and fill of the tranny (only 15K miles on it) and it looked like engine oil. That must explain how great T-IV!!!
I find that WS shift quality is so much better then T-IV.
UOA numbers haven't been compared. T-IV is just as poor of a performer. Actually, T-IV looks worse then WS.
Any universal/multivehicle ATF mentioning T-iv/3309 should be used in place of T-IV. RoyalPurple, Mobil1, Amsoil, Castrol, Pennzoil.... have ATF for you.
Concerning WS, products are available from Amsoil, Redline, Amalie....that are thinner at normal operating temperatures for the improved MPG.
I find that WS shift quality is so much better then T-IV.
UOA numbers haven't been compared. T-IV is just as poor of a performer. Actually, T-IV looks worse then WS.
Any universal/multivehicle ATF mentioning T-iv/3309 should be used in place of T-IV. RoyalPurple, Mobil1, Amsoil, Castrol, Pennzoil.... have ATF for you.
Concerning WS, products are available from Amsoil, Redline, Amalie....that are thinner at normal operating temperatures for the improved MPG.
I used Amalie Universal Full. Syn. in my '04 4WD Highlander 5-speed tranny. Seems to down shift when accelerating faster. Said T-IV and WS approved??
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I use to work at TMMI, Just bought a '04 Highlander 7 pass, 4WD for my family wioth 106k on the clock. Can you help me take it to 300k?
trans fluid, non OEM
Linear Mode
