Repair-It

Back to fluid to use. I think I'm still leaning toward Valvoline Maxlife for cost/fleet application reasons. I was fascinated by this note on a Benz forum about a Motul Dexron VI here:
https://mbworld.org/forums/gl-class-x16 ... nny-2.html

The specific note is that it says "236.17 (except FE benefits)".

Usually those are at the expense of life, so maybe I do want the universal in lieu of the Benz approved. But that's only one of probably hundreds of variables...

I get the note - the Maxlife is thicker, so that will remove the fuel economy benefit of the lower viscosity introduced with 235.15.

I still don't like the idea of modifying the viscosity of transmission fluid. It's a pretty tightly calibrated system that, while it can and does adapt, is at least expecting a baseline viscosity. I probably wouldn't do it. The MB fluid is expensive though. I think $26/liter?

The specific non-FE quote is actually about a Motul product - I think I'd argue that the viscosities between Maxlife multi and the spec I was looking at for Lifeguard 8 appear so equivalent that I don't think there's any measurable difference. Maybe Motul is thicker, or maybe somehow there's some special stuff that helps the Benz fluid improve fuel economy...

ATF134 which is 236.14 (red, older fluid, used in my E55 722.6 and S550 722.9): https://images.oreillyauto.com/parts/im ... NC4wLjAuMA..

PRODUCT ATTRIBUTES
Appearance Red
Density at 15°C 0.848 g/ml
Flash Point >206°C/>402°F
pH Value N/A
Dynamic N/A
Kinematic Viscosity at 40°C 29.6 mm²/s
Viscosity Index 185

ATF134FE which is 236.15 (blue, newer fluid for A89 coded 722.9 applications, post 2010 or so):
https://images.oreillyauto.com/parts/im ... f134fe.pdf

PRODUCT ATTRIBUTES
Appearance Blue
Density at 15°C 0.841 g/ml
Flash Point 190°C/374°F
pH Value N/A
Dynamic N/A
Kinematic Viscosity at 40°C 18 mm²/s
Viscosity Index 160

That viscosity is WAY thinner for the FE fluid, and Maxlife magically claims they can handle both applications with a single fluid.

I believe 236.17 has a similar viscosity to the 236.15 update. However, Mercedes (and the aftermarket fluids that target these specs) say you CANNOT interchange 236.14 with 236.15. Shell/Pentosin and Mobil say this specifically (and so does Mercedes). I did see the possibility on FCP Euro that you can use the 236.17 (gold/yellow) in 236.15 applications which tells me they are equally thin. The Maxlife I believe is similar in viscosity to the 236.14. Again it makes me wonder what Valvoline is up to there.

Application summary so you can follow along:
236.14: 722.6 (5-speed) and pre-A89 update 722.9 (7-speed). This basically covers all 5 and 7-speed applications to 2009, 2010 or somewhere in that range.
236.15: A89 update for the FE spec, thinner fluid. They didn't just change the fluid - they changed the pans, filters, possibly frictions (looking for proof though), and added the A89 coding to the datacard. We can see how much thinner it is. This would cover all 7-speed applications from 2010 or 2011 through the end of the 722.9 run (2016 or so depending on application but some ran later).
236.17: 9 speed. New fluid spec, again. 2016/2017 and on generally.

Point 1: It would be impossible for Maxlife to actually meet the specs it claims to be compatible with. It's not a question of them spending money on the certification. I think they would be rejected on the basis of viscosity, color and probably some other things.

Point 2: It is also possible that Maxlife is good enough as an overall fluid, and a thicker fluid ONLY has the downside of losing the improved fuel economy benefits. In general, fuel economy regs have forced the introduction of increased complexity and frankly reliability issues for long term ownership prospects. It's just that the viscosity difference seems rather large. Maybe Maxlife is similar to the ZF fluid but it's probably way thicker than 236.15 (and 236.17).

https://images.oreillyauto.com/parts/im ... NC4wLjAuMA..

According to this the recommendations for MB end at 236.14.

Yet on here it lists the newer ones. https://sharena21.springcm.com/Public/D ... 162d889bd3

Their note about CVTs suggests that they may have reformulated in 2021 or so and perhaps the O'Reilly's info is pre-reformulation. You know it would be interesting to talk to a Valvoline engineer.

I dunno, this smacks of trying to run a single oil brand and viscosity across an entire range of applications. There was a time, particularly if you lived in a warmer climate, that you COULD have used your "all fleet" 15W-40 in cars, trucks, but I feel like we are 20-25 years past that being a good idea.

kevm14 wrote: ↑Mon May 06, 2024 9:25 am That viscosity is WAY thinner for the FE fluid, and Maxlife magically claims they can handle both applications with a single fluid.

I believe 236.17 has a similar viscosity to the 236.15 update. However, Mercedes (and the aftermarket fluids that target these specs) say you CANNOT interchange 236.14 with 236.15. Shell/Pentosin and Mobil say this specifically (and so does Mercedes). I did see the possibility on FCP Euro that you can use the 236.17 (gold/yellow) in 236.15 applications which tells me they are equally thin. The Maxlife I believe is similar in viscosity to the 236.14. Again it makes me wonder what Valvoline is up to there.

https://www.mobil.com/en-hu/passenger-v ... atf-134-fe

Mobil ATF 134 FE is designed for the Daimler automatic transmission type 7-G Tronic Plus. The below articles are introduced for all markets where the predecessor product (Mobil ATF 134) has been sold previously. Mobil ATF 134 FE is only miscible with other officially approved MB 236.15 ATFs and not backwards compatible with previous MB-ATF specifications.

kevm14 wrote: ↑Mon May 06, 2024 9:25 am 236.15: A89 update for the FE spec, thinner fluid. They didn't just change the fluid - they changed the pans, filters, possibly frictions (looking for proof though), and added the A89 coding to the datacard. We can see how much thinner it is. This would cover all 7-speed applications from 2010 or 2011 through the end of the 722.9 run (2016 or so depending on application but some ran later).
236.17: 9 speed. New fluid spec, again. 2016/2017 and on generally.

https://www.fcpeuro.com/blog/how-to-cho ... sion-fluid
The “Plus” model (which can go by another name internal to Mercedes, the NAT2FE+) is effectively a redesign and improvement of the original 722.9 (internally, the NAT2). Hardware improvements include a revised torque converter using a world-first centrifugal pendulum damper—which helps longevity, cooling, and eliminating slip—an auxiliary oil pump for adequate stop/start lubrication, an operating system specifically designed around “Eco” drive modes, and transmission gearset materials designed for reduced friction. As such, the Plus offers quicker and smoother shifts as the byproduct of those hardware and software upgrades.

With those improvements, Mercedes determined a new fluid with different characteristics was needed. The early 722.9 model used a red fluid, more in line with traditional ATF. The Plus, however, used a blue fluid with much lower viscosity to help with the redesigned components aiming at reduced friction. Neither fluid is compatible with the other’s transmission, so ensure you know exactly what you need before pouring any in.

BTW option code A89 is called "reduced friction."

kevm14 wrote: ↑Mon May 06, 2024 9:25 am I did see the possibility on FCP Euro that you can use the 236.17 (gold/yellow) in 236.15 applications which tells me they are equally thin.

https://www.fcpeuro.com/blog/mercedes-b ... ifications

On the 7G-TRONIC PLUS transmissions, we recommend running the latest version of the ultra-low viscosity fluid by Mercedes (gold in color). Unfortunately, this fluid is not compatible with the earlier 7G-TRONIC transmissions (red colored fluid) but is fully compatible with the PLUS transmissions that use the blue colored fluid.

So at least according to FCP Euro the 236.17 and 236.15 are....compatible in the application sense.

Except these guys don't agree and they are one of the few actually approved for 236.17:
https://www.blauparts.com/mercedes-tran ... 03-1l.html

RAVENOL ATF M 9-G Serie must not be used in older Mercedes Benz 5 and 7-gear automatic transmission, which require automatic transmission oil according to the MB approval MB 236.10, 236.12, 236.14 or 236.15.

The problem is...

From Pentosin.

PENTOSIN ATF 134 FE Premium Performance, Low Viscosity Automatic Transmission Fluid

DESCRIPTION
Pentosin ATF 134 FE was developed to further optimize gearbox efficiency of the latest generation Mercedes-Benz 7-G Tronic Plus (NAG II+) automatic transmissions. This advanced OEM Approved fluid is the lowest viscosity ATF available in the world, providing impressive fuel economy potential and low temperature performance. IMPORTANT NOTE: Pentosin ATF 134 FE is NOT downwards compatible with previous MB-ATF specifications.

This checks out, too, when you look at the cST spec for 236.15. It is very thin (and again I am extending this to 236.17 - I will see if I can find a spec to confirm). And it sounds to me like the entire transmission was update around it.

I really wish there was a way to know which fluid will help the Benz transmission live the longest, whether there is a viscosity difference or not.
Anecdotally (I haven't done any research), I believe Dexron VI synthetic was thinner than Dexron III (conventional), yet backwards-compatible-listed for almost anything/everything. I think the philosophy is that the thin-film performance of this lower viscosity fluid must be adequate even where heavier oils are called for. I also wonder if it's much more thermally stable, making it's viscosity at high (normal?) operating temps adequate to not drive up torque converter stall speeds, etc.

This is also a dumb statement, but I believe MaxLife is the "universal" equivalent/generic of Dexron VI synthetic and similar to the 5W-40 Shell Rotella T6 synth vs. 15W40 T4 conventional "OK" in every application (which interestingly enough there's now a T6 15W40 min-oil-consumption, potentially to address "universal" oil consumption concerns I guess). And Dexron VI was thin-ish and works in anything Dexron III, which I think serves the basis of the "universal" application.

So Valvoline Maxlife is on the "relatively" thin end of the viscosity spectra. Does that make it as-thin as 236.17? I don't know - it was weird that I couldn't find viscosity ratings quickly. I'll have to find an approved 236.17 and try to pull the data sheet. But as we've discussed, viscosity isn't the only factor, the whole additive package matters. There's also a chance that Benz erred on the side of optimum fuel consumption and "skimped" out on viscosity (and possibly additive package) to get the fuel economy/transmission efficiency up. If that's the case then there's a chance that MaxLife could extend the transmission life better than an approved 236.17 fluid.

I had read horror stories about Honda's being very sensitive about fluid type, and was surprised that this "Walmart" oil carried the Z1 recommendation. That's what I ran in the 2008 Odyssey from 105k miles until 218k (changed about 1/2 inventory every 18-20k mi), with no transmission issues ever noted. Looks like Honda's "updated" DW-1 spec is thinner and people are having issues in old transmissions with it, and at least one forum says folks are switching to MaxLIfe as the "fix"...

https://www.odyclub.com/threads/honda-d ... fe.325513/

rpaoness wrote: ↑Tue May 07, 2024 2:46 pm I really wish there was a way to know which fluid will help the Benz transmission live the longest, whether there is a viscosity difference or not.

Agreed - but all we can really do from here is compare specs and make an engineering assessment.

rpaoness wrote: ↑Tue May 07, 2024 2:46 pm Anecdotally (I haven't done any research), I believe Dexron VI synthetic was thinner than Dexron III (conventional), yet backwards-compatible-listed for almost anything/everything. I think the philosophy is that the thin-film performance of this lower viscosity fluid must be adequate even where heavier oils are called for. I also wonder if it's much more thermally stable, making it's viscosity at high (normal?) operating temps adequate to not drive up torque converter stall speeds, etc.

My research on that reveals that GM errantly back-applied DEXRON VI and it is known to cause problems in plenty of DEXRON III applications. It is a better fluid, though, so one of the approaches is to try it, and if the shifting seems the same or improved, stick with it. If it starts to shift weird (or laggy TCC apply), probably switch back. Problem is, if you apply this to the 9G, you have wasted a ton of time and some money experimenting.

rpaoness wrote: ↑Tue May 07, 2024 2:46 pm This is also a dumb statement, but I believe MaxLife is the "universal" equivalent/generic of Dexron VI synthetic and similar to the 5W-40 Shell Rotella T6 synth vs. 15W40 T4 conventional "OK" in every application (which interestingly enough there's now a T6 15W40 min-oil-consumption, potentially to address "universal" oil consumption concerns I guess).

I made that argument before. Well I made it based on the old 15W-40. It's more like....the engine calls for a new-spec 0W-16 (or 0W-8 God forbid), and you say, nah, I'm gonna run my favorite Shell diesel 5W-40. PROBABLY not a good idea. And with your specific DEXRON VI example, it's awkward because Maxlife is not really recommended in those applications (and I'm not sure why). Just saying.

rpaoness wrote: ↑Tue May 07, 2024 2:46 pm So Valvoline Maxlife is on the "relatively" thin end of the viscosity spectra. Does that make it as-thin as 236.17? I don't know - it was weird that I couldn't find viscosity ratings quickly. I'll have to find an approved 236.17 and try to pull the data sheet. But as we've discussed, viscosity isn't the only factor, the whole additive package matters. There's also a chance that Benz erred on the side of optimum fuel consumption and "skimped" out on viscosity (and possibly additive package) to get the fuel economy/transmission efficiency up. If that's the case then there's a chance that MaxLife could extend the transmission life better than an approved 236.17 fluid.

I couldn't find a 40C cST spec for the 236.17. I believe it is about as thin as the 236.15 which is substantially thinner than 236.14 (which is what I believe the Maxlife is similar to in viscosity). EDIT: I was right.
https://forums.mercedesclub.org.uk/inde ... on.185872/

It's actually a touch THINNER (but about the same) as the 236.15 (which was "the worlds thinnest ATF" or whatever that quote above says).

I agree with the end goal - maximize transmission life. That is more important than saving $40 on a fluid change, or the convenience of stocking one fluid. And it's more important than 0.7 mpg. But lacking supporting information, the OEM fluid is the only way to go (or at least a fluid that is formulated to meet 236.17 even if it doesn't actually have the approval - Rockauto carries a few). The MBworld thread on a DIY 9G fluid service has zero Maxlife content. Do you really want to be the first?

Side note (new post): this transmission is way older than I realized. Well, "way" is a relative term.

https://en.wikipedia.org/wiki/Mercedes- ... ansmission

But this claims 2013 production and then initially being offered in the 2014 E350 Bluetec (diesel). It's not clear if this was available in the US but I guess it doesn't matter.

FWIW, the ZF8 gen 1 was released in 2010-ish. It says 2nd gen was 2014 so maybe that's what's in your Jeep. 3rd gen in 2018.