There are valid reasons why ZF insists on a specific fluid for a specific transmission or range of transmissions. Due to CAFE standards and other legistlative regulations, automakers are under increasing pressure to improve the fuel economy of their vehicles, and they pass that pressure along to their suppliers. Transmission manufacturers are constantly working to reduce internal losses due to friction, stiction, hysteresis, inertia, etc.; to increase gear count to keep engines operating in their most efficient ranges; all while reducing the overall weight of the gearbox.

It seems perfectly reasonable that to achieve those goals the transmission fluid might need to have specific properties, such as viscosity index, kinematic viscosity, thermal breakdown resistance, friction modifiers, etc. If Mobil 1 or Mercon SP or any other fluid have all the right properties/specifications, they should work fine. For owners who don't have the time or knowledge to research and compare fluid properties themselves, or who don't trust the opinions of others, ZF Lifeguard 6 is the safe choice. When you amortize the difference in price over the miles/years the fluid will be in service, the incremental cost is low.

I read recently that the ZF 6HP26 gearbox was used in the Kia Mohave (I think) and Hyundai Genesis. It would be interesting to know what a Hyundai/Kia dealer would charge for transmission fluid....

 

I understand the spec for the oil is from Shell. M1375.4 -- any oil that meets it should be OK.

 

6L of lifeguard 6 Shipped cost $280Aud,
6L of Mercon SP + shipping was $205Aud

I still see no good reason to try and save $75Aud

And if the spec from the other supplier is not perfect you risk your trans for $75
What would a rebuild cost, a lot more than $75

The choice is yours but I am sticking with the Lifeguard 6

On a side note one well known oil supplier here in OZ that has a loyal following and markets as a performance oil brand used to sell a trans fluid that claimed it met lifeguard 6, Mercon SP and Shell specs. A lot of indi's started using this for refills. Lots of ZF's started failing and low and behold they dropped the Lifeguard 6 from the label.

You can each make your own decision but I just cant see why you would risk it for a few bucks

Just my 2 cents worth its up you what you do

Cheers
34by151

 

In Australia, it might be a close or at least semi-close race.

But in other areas, it is not.

Mercon SP in North America is dirt cheap. Even cheaper
when looking at the Valvoline equivalents. Maybe $20
for a gallon jug.

Ford specifies Mercon SP in the ZF in the few models
where they use it.

For the Valvoline Dex/Merc Maxlife I use in my Merc transmission,
2 jugs is about $40, or half of just the difference described.

At that price, it becomes a commodity item.

++

 

As I said "make your own decision"
I'm not ragging on anyone that chooses the alternate options

But even at that price I still would use the Lifeguard 6
Id still go lifeguard of the others were free

For me the risk does not equate to the bills of a trans rebuild if it goes pear shaped

Just my 2 cents, it's your car and you are free to choose as you wish

Cheers
34by151

 

I sell low cost safety razors. My refills, however, are quite expensive. I recommend only my brand of refills at risk of death, disease. famine and pestilence. My refills are made of unobtainium and meet specs established by the North Korean space agency and my very, very honest global warming government scientist.


Hay! It works for me and has worked since way before P T Barnum. My God how the money rolls in. I'm a just saying.

 

Hyundai told me 225$ per quart.

The issue is not that mercon won't work, it obviously does work in the ford models.

The issue is changing viscosity and such, I am sure we have all read and heard the true stories of changing fluid, with the identical fluid brand, at higher milage and nuking a converter or clutch because of the change.

So in my opinion, and the opinion of most mechanics I talk to, stick to the same fluid that is in the Trans and do not mix it. Common sense really.

It happens. Often. Hence the debate on whether or not to change the fluid at all

 

I do know that for example on an Accura if the factory ATF is not used it is very possible you will have some flares and/hard shifts. Not all cars exhibit it but we are talking a $3-5000 transmission here.

Also on late model manual transmissions some have tried using a regular lube or synthetic lube and after awhile exhibit clashing of 2nd or 3rd gears. If operated continually like this, the syncro wears down along with the gear. Then it is expensive to repair.
The cause is the syncro is manufactured with substances that have a predetermined amount of friction that will stop the gear in order to engage it. For this reason the spec for the lube is unique and sold at the dealership for $16 a quart (many hold only 2 qts).

My point is why risk an expensive repair for a few dollars.
It may be okay for say. plug wires etc but not high dollar items.
Weigh the risk first.

 

The attached file compares those properties that I have managed to find for various ATFs; make what you will of them

 

I am wondering whether ATFs having similar or even equal physical parameters (viscosity, flash point, etc.), thereby qualifying for use in a given gearbox, may differ in the long term because of their chemical stability.

Lifeguard 6 may well incorporate traces of some chemicals that enhance its durability while other ATFs of similar chemical composition (regarding the main elements) would not.

And that could explain the difference in performance in the long term...

 

Assuming you change the trans fluid every 50,000km as I do you are still spending 5 times as much on engine oil and filters

So in those terms the lifeguard is not expensive at all

Im not going to try and save under $100 Aud over 50,000km at the risk of a trans rebuild over the long term, not on the Jag

Our Mitsubishi Magna has 200k on it and still has the original fluid.
Given it worth next to nothing now Ill drive that one till it dies as I don't care if the trans fails and even if it did I could replace it for a few hundred

The same cant be said about the ZF trans

Cheers
34by151

 

very interesting and tempting too.

I do know that some of these zf's can eventually over time develop a 4-3 chirp on a hard down shift.
a fluid change often is the solution.
to me it seems to indicate there must be a fine balance of additives which work specifically in this model zf to address any of its quirks.

similarly i had a power steering noise that went away when i got an additive from the dealer. somethings are strange i know but the engineers often have the answers.

 

Mine had the "bark" on downshift, here's an old video of the car at around 95'000 miles


I had the pan/filter, sleeve, bolts and fluid changed out, having bought a complete kit from a supplier in the UK

The fluid came in plain white bottles identical to the ZF ones, but without the ZF label, just said "Shell M-1375.4"

The bark was gone.

At the time (end of 2012) the ZF fluid was expensive, even buying it from BMW dealers in Germany, and I would have still had to buy the pan, sleeve and bolts separately. As this fluid was not branded I have no idea if it was genuine ZF that had been slipped out the back door, or Mercon, or something else.

 

Partick the Cat,

Thank you for your research! I've copied it and begun adding a few other options for my own reference. Comparing the data is very instructive:

1. The available data sheets don't fill in all the blanks for Lifeguard 6, but the data we have all perfectly match the Shell M1375.4 specification.

2. Mobil 1 and Pentosin ATF1 have pour points equal to the Shell spec, and Pentosin ATF1 LV has a kinematic viscosity @ 100C equal to the Shell, but otherwise none of the fluids besides Lifeguard 6 matches any of the Shell M1375.4 specs. Some are close, but no other specs are identical.

Whether the differences are significant enough to cause performance issues might be impossible to know without testing the fluid in your transmission, but it's clear that neither Mercon SP nor Mobil 1 are the same fluid as Lifeguard 6.

Given all the reports of transmission problems attributed to mixing fluids, I don't think you would want to risk using a fluid other than Lifeguard 6 unless you did a very thorough flush to remove as much of the old fluid as possible.

3. It seems important to note that Shell M1375.4 / Lifeguard 6 is a a very low viscosity fluid. Of the fluids on your spreadsheet, only Pentosin ATF1 LV has a lower kinematic viscosity @ 40C, but its overall viscosity index is higher (168 vs. the Shell's 151). Lifeguard 8 has a slightly lower kin visc @ 40C of 26. Unfortunately, ZF doesn't provide viscosity indices for comparison.


NOTES:

1. A 2007 datasheet for Lifeguard 6 lists the flashpoint at 200C and kinematic viscosity @ 40C at 28, but later data sheets (2008 and 2013) agree with your spreadsheet figures, 210C and 26.8 respectively.

2. The Mobil 1 data sheet I found listed its viscosity index at 176, but your spreadsheet had it at 167. I wonder if the last two digits had been transposed, or did you find a data sheet with a different spec?

Something I learned while researching fluid for the ZF 4HP24 gearbox in our '93 VDP is that, while many ATF fluid manufacturers claim their modern fluids are "backward compatible" in older transmissions, ZF does not agree. They recommend Lifeguard 8 in certain Audi 6-speed boxes, but in all others they still specify Lifeguard 6. They don't recommend Lifeguard 6 in 5-speed boxes, it's Lifeguard 5 only. And in our old 4-speed box they do not recommend the newer fluids like Dex/Merc or Dexron VI, they still recommend Dexron III. That tells me the ZF engineers know the proper performance of any of their transmissions depends on the use of a fluid with very specific properties. I, for one, am not going to try to second guess them.

Here the link to ZF's recommended oils for various transmissions:

http://www.zf.com/na/content/media/u...omendation.pdf


Great work, Partick the Cat. You've affirmed my gut instinct that unless I can find some Shell M1375.4, Lifeguard 6 is the only choice for me.

Cheers,

Don

 

My reasoning for using Mercon SP is that my 04 XJ8 now has over 190,000 and has no value except to me. Using insanely expensive ZF fluid is just plain stupid. Anybody who thinks that a 6HP 26 tranny in a Jag, BMW, Rolls-Royce, Range Rover or anything else is any different from the 6HP 26 in a Lincoln Navigator (except for the bell housing bolt pattern) is an idiot. A case of Mercon SP (12 quarts at O'Reilly was about $80. A pan/filter assembly from Rock Auto was around $100. And a year and 20,000 miles after the transmission service it's shifting fine. So if some of you guys want to waste money on a $2000 used car have at it!

 

Not so sure if some one chooses to use an expensive ATF is an idiot. Maybe overly cautious. Generaly speaking, idiots think only their way of doing things, is the correct one.

 

Hi kratzerap,

Your opinions about other Jaguar owners are fascinating, but we would be more interested in learning how well your transmission performs after the switch to Mercon SP. For example, does your car now drive like a Lincoln Navigator? Or does it shift just as well as it did when it was new? Were you having rough shifts or other issues before the fluid change, and if so, were they eliminated after the change? How thoroughly did you flush the old Lifeguard 6 out of your gearbox before you filled it with Mercon SP? How closely did you follow ZF’s instructions for the fluid change? This kind of information would be helpful to furthering the collective knowledge of the forum.

The ZF transmission in a Lincoln Navigator may be identical to the one in a Jaguar X350, but I have not yet been able to confirm it. Ford calls the Expedition/Navigator transmission a 6SHP26, and they use their own part numbering scheme for internal service parts.

For all or most of the European vehicles that use the ZF 6HP26, the torque converter appears to be the same, but unfortunately no information is given about Ford U.S. vehicles. See page 13 of this document:

http://www.zf.com/media/media/docume...28_Catalog.pdf


The Mechatronics (combined valve bodies/control modules) have different part numbers for versions fitted to various BMWs, Land Rovers, Range Rovers and Jaguars, and different part numbers within those makers' ranges depending on the transmission part number. See pages 5-7 of this document:

http://www.zf.com/media/media/docume...n_Parts_EN.pdf


The version used in Audi/Bentley vehicles with the W12 engine is so different that ZF specifies Lifeguard 8 fluid even though it's a 6-speed box. See page 2 of this document:

http://www.zf.com/na/content/media/u...omendation.pdf


This interesting document (and a couple of the ZF parts catalogs) show that there are at least two different types of Mechatronic installed in 6HP26 transmissions, the E-shift version or E-version, and the M-shift version or M-version. This document also contains the warning, "Do not mix different oils unless this is expressly prescribed" (presumably by the automaker or ZF):

http://www.apra-europe.org/dateien/d...chatronics.pdf


I have not yet found a cross-reference of Ford and ZF part numbers. The Ford part number for the 6SHP26 “Valve Body” is 7A100, so without a cross reference it’s impossible to know if it is identical to one of the Jaguar versions (e.g. ZF part number 1068 198 943 06). The Ford version may indeed be identical to one of the versions used by Jaguar as you assert, but it seems at least technically possible that the Ford U.S. version might have been adapted to work with Mercon SP rather than Lifeguard 6. Note that for European Ford vehicles, ZF specifies Lifeguard 6 only.

Without confirmation from ZF, I’m not ready to simply assume anything. Any additional information you can provide will be welcome, especially verifiable facts.

Cheers,

Don the stupid idiot

"Enquiring minds want to know."

 

+1 on Dons comments

kratzerap, I think your post is a little harsh and I still cant see your argument is valid from a risk vs cost point of view

As I posted you are free to make your own choices. I encourage you to question others choices including my own but name calling is not in the spirit of this forum.

You might want to read these 2 links

This one deals with trans issues when using cheaper fluids the last paragraph is the most damming

ZF 6HP26 Transmission Introduction - Furitech Automotive

This is the media release that Penrite issued after removing lifeguard 6 from there ATF fluid label. The only change was the label they still claim Mercon spec

http://www.penriteoil.com.au/tech_pd...VELOPMENTS.pdf

So when an oil supplier removes Lifeguard 6 from the label but keeps Mercon due to customer failures it tells me right away that it is not a good idea long term

Cheers
34by151

 

Interesting comments. I have a '06 xjr with 95K on it and have all the records from purchase date to present. No trans fluid changes. I just googled ZF 6hp26 and found that ZF recommends fluid changes (ZF fluid of course) at between 50K to 70K. They recommend only the new pan with built in filters, fluid change and refill. No concerns raised with converter or cooler. So for me, that advice will to the trick, will buy the pan/fluid and have it changed. Thanks for all the interesting comments.

 

With 160,000 miles on the odometer the transmission in my '04 XJ8 started shifting rough on the 1-2, 2-1 downshift and it would trigger the "gearbox fault" message and remain in 4th gear and not shift at all. After changing the filter/pan and refilling with Mercon SP one year ago, and 190,000 miles later, it's shifting fine. What's the risk of experimenting with a car that's virtually worthless. I could spend more than the car is worth using Jaguar and ZF approved fluid and procedures. Frankly, I'm thinking about switching to Dexron 6 just for the hell of it just to see what happens. After all, I really prefer to use full synthetic. BTW, several transmission shops told me that the tranny needed a complete overhaul before I decided to try a fluid and filter change.