Originally Posted by dave1251
Originally Posted by BlakeB
Originally Posted by dave1251
Originally Posted by BlakeB
What about a TES-295 clone that's recommended for Dexron III applications. Dexron III superseded Dex II and should work fantastically and be a lot closer to the original fluid spec Viscosity. I have a particular fluid in mind, but it's not Toyota branded, so you probably won't like it. What say you?
If you are saying this you don't know a thing about viscosity.
OP what you have will work better the DEXRON II.
Elaborate please.
DEXRON III was out of viscosity spec within 10K miles of useage. By the time it reached it's recommended change interval it was close or into the 4cst range. Thus DEXRON II/III was thinner then modern DEX VI fluid. If you stepped up with Mobil One or Boutique ATF it still sheared into the 5's CST range at 10-20K miles of usage and ended up thinner then current DEX VI fluid. So by today's standards to be closer to a DEXRON II/III it's a terrible comparison.
While what you are saying is true, TES-295 type fluids are very shear stable and should maintain a higher viscosity than these newer LV type fluids. I think a higher viscosity fluid is important in older, more worn transmissions. As fluid thins down, the line pressure is ramped up by the pcm to compensate, thinner fluid requires more volume to maintain the same pressure. The PCM can also raise the line pressure to compensate for worn clutches and leaking valves/bores within the valve body. A more viscous fluid allows for more pressure without maxing out the volume capabilities of the pump. Any extra fluid volume that isn't needed to maintain operating pressure is returned to the sump or suction side of the pump by the pressure control valve.
Think about the people that add Lucas trans fix (almost impossible to pour while cold) to their worn out ATF and it goes back to shifting correctly.
I'm not sure about the A340E/F transmissions, but some transmissions will prioritize line pressure over converter/cooler flow.
I agree with you that a lower viscosity fluid will absolutely work, but I believe that a high quality (shear stable) higher viscosity fluid such as a TES-389/295 fluid will give you a larger safety margin in the most extreme situations.
These TES type fluids have excellent low temp flow properties as well. In fact GM recommends TES-295 fluid in place of Dexron VI in my 3500 HD's Allison transmission in places with extreme cold temperatures.
If you take a look at the Brookfield viscosity of the Delo Syn ATF HD I mentioned earlier, it has a BV of 11,400.
Dexron III(H) specifies a max of 20,000 and Dexron VI specifies a max of 15,000.
Some of the licensed TES-295 fluids have a lower Brookfield viscosity than that.
All of that said, if the 4Runner in question is just a daily driver that doesn't tow or off-road frequently, I think Dexron VI or Maxlife would do just fine. In extreme use scenarios I would be looking towards a synthetic ATF with a little higher viscosity personally. For whatever it's worth, licensed TES-295 fluids go through the same oxidation testing that Dex VI does, but Allison tests for 600 hours whereas GM only does a 450 hour test.
