Mazda M-III ATF Substitute

[Number_35]

Any chance you could provide an update?
Any shifting/performance issues you've noticed since your "drain and fill" with Maxlife MV?

I'm curious to see if there are any shifting/performance issues using a lower viscosity fluid (Maxlife MV fluid viscosity is 5.9cst @ 100c) vs other user recommended fluids (ie Idemitsu M, Mobil 1 ATF, Castrol Transmax import...all have viscosity values in the 7.1 - 7.4cst @ 100c range).

I haven't driven the van since then, but Jr and I will be doing more work on it (including a transmission-pan drop, filter change, and more Maxlife) when weather permits.

I'll report back.

 

[martinq]

Any chance you could provide an update?
Any shifting/performance issues you've noticed since your "drain and fill" with Maxlife MV?

I'm curious to see if there are any shifting/performance issues using a lower viscosity fluid (Maxlife MV fluid viscosity is 5.9cst @ 100c) vs other user recommended fluids (ie Idemitsu M, Mobil 1 ATF, Castrol Transmax import...all have viscosity values in the 7.1 - 7.4cst @ 100c range).

Viscosity should have very little effect unless you are exceeding the fluid's operating temperature range (overheating).

When you operate the transmission with a fluid temperature of 0C / 32F, MaxLife ATF has a viscosity of ~200cSt.
As the fluid warms up that viscosity changes, at 50C / 122F it is now ~20cSt. The viscosity has dropped by an order of magnitude (take a zero off). Wow! What horrors!!

What happens when that 20cSt viscosity fluid heats up and drops to 10cSt and then to 5cSt? Does the transmission keep working? Yes.
What happens when you operate the transmission with a fluid viscosity of 800cSt? Does the transmission keep working? Yes. Is the transmission destroyed? No.

Changing the operating viscosity by 10 or 20% has very little impact on the operation or durability of the transmission as long as it is within the operational range (5000 - 5 cSt?). What is very important is the cleanliness of the fluid and the quality and type of additives in that fluid.

TLDR, clean / fresh / "cool" fluid is good for a transmission, it doesn't care about a viscosity change from 7cSt to 6cSt.

 

[lmdshepherd]

Changing the operating viscosity by 10 or 20% has very little impact on the operation or durability of the transmission as long as it is within the operational range (5000 - 5 cSt?). What is very important is the cleanliness of the fluid and the quality and type of additives in that fluid.

Thanks!

Yes, I'm well aware of the theory, and the fact that a small viscosity change should (in theory) have little to no adverse affect to the transmission's operation in normal operating conditions.

What I'm looking for is "real world" feedback (ie people who have actually used the lower viscosity ATF (6cSt @100c compared to the OEM recommended 7-7.4cSt) in their cars, not just talked about it) especially given the OP and I have very similar transmission (I've got the later 5 speed version of the OP's transmission).

From what I've read on BITOG (and other forums), the real world feedback indicates the vast majority of users suffer no adverse effects (assuming the ATF fluid manufacture states their fluid is compatible).

For example, this post from earlier in this thread:

I used Maxlife for over 200k miles in my 2001 Mazda that called for M-III. Zero issues.

This is exactly the feedback I'm seeking. Maxlife's viscosity has been around the high 5's/low 6's for many years (image below taken from this 2012 pdf: Maxlife 2012 pdf)