So, after intensive research (and I really do have a headache now).

From what I can gather, a less expensive alternative fluid that still meets spec for my ZF 5HP24 trans (2001 XK8 4.0L) is any fluid that meets Mercon V spec . . . NOT Mercon SP.

So, Ford trans fluid is a Mercon V spec fluid ($6/quart). Anyone here use that in their ZF 5HP24 trans? Any problems?

Apparently, many are saying that you should not mix any Mercon V with SP.

Amsoil Signature trans fluid is pretty cheap at $147 for 12 qts and that meets Mercon V, LT1141, Dexron II and III specs as well.

Mobile 1 ATF is $11/quart. But, I can't find out if it meets spec for this trans.

Pentosin Synthetic ATF apparently also meets spec. But, I'm not totally sure.

Oy.

 

When I've done a pan and oil change, I've used the ZF fluid only, because I don't want to mix. But, when I had my transmission rebuilt, my mechanic gave me his full assurance that the Castrol Synthetic ATF was compatible with the transmission. I've driven over 20,000 miles since, and it shifts up and down like butter...better than when I first bought it.

 

I have the amsoil in mine along with the blue top solenoids for a bit over a year now....Transmission is great@..Motor currently not so much lol

 

I have a headache beating the 'dead-horse' ZF 5HP24 fluid debate!!!
Both of you are discussing ZF 6HP26 or W5A580 (722.6 Mercedes) fluid compatibility for a 5hp24???????

I use VW G52 162 A2 or Pentosin ATF1 or ESSO LT71141 or ZF Lifeguard 5 because they are all the SAME and they mix with the fluid ALREADY in the gearbox.

As the owner of the car you can use whatever you want.
Drain and fill, flush, mix........................ do WHATEVER you want.

This has been argued for a decade?????

bob

 

the fluid question is this , as far as hydrolics , there all compatible , lube ,there all compatible ,
where atf is different is the friction properties with the clutch discs used . oe clutches should have oe oil to achieve oe clutch coheshion . aftermarket clutches can run regular fluid , regular fluid can be run with zf,s but shift feel may be noticed .
bottom line is , it's all about friction properties

 

Obviously there is still confusion! I wonder how many know there are both ZF 5HP24 and ZF 6HP26 transmissions in the XK8?

I just ordered the Amsoil Signature.

 

I would guess that most owners who have been forum members for at least six months or so (and take the time to read at least some of the many ZF problem threads) will know whether their cars have 5HP24 or 6HP26 transmissions, and also realize that the required ATF specs for each are quite different. Many of us could collaboratively write and publish a book on this subject....

Good luck with your upcoming drain-and-fill, and be sure to update your results afterwards....

 

this is what I'll use.

 

AND the Supercharged 4.0 uses the 722.6 Mercedes gearbox!!!!!!!!!

Three different boxes for the XK.

bob

 

For some of us this may be the first time dealing with our transmissions and what we should be doing when we change fluids. So it may be 10 years for you it may be new to us in doing these changes and not wanting to F anything up. Sure one can search but you get a millions threads and opinions from over those 10 years so sorry if we start new threads.

 

Indeed. And, I might add, 10 years of confusing and far from definitive posts on the subject.

 

So this post is any different on opinions????????????????????????

bob

 

While this is in play again . . . .

What is the fluid spec and compatible fluids for the 6HP26? Not that I have rushed out and bought a later model XK8 but my Kia Borrego has this transmission and it is time for a fluid change.

None of the several auto shops in my small rural town have convinced me that they are educated/experienced enough to give me a straight answer that I believe. The quick lube said that their universal ATF with a custom set of friction modifiers would work just fine. They even had a computer printout to confirm it.

. . . maybe not . . . .

 

I'd just think over TEN years we would have a history of what has worked, what has not, 10 years of more knowledge of this process for this now hitting some of us. I know my 03 needs a flush, getting the here and there hard shift. Appears the Mercon SP is what I should use in my car with no use of a friction additive and maybe having the adaptive driving stuff re flashed though I don't get why just taking battery off the car for a bit would clear that????.

 

The problem is members are trying to substitute Factory spec brand fluids with something cheaper to ease their wallets. Which is fine and understandable. If you are fully confused pony up and buy the OEM no questions there. Since most will be doing this once you have to balance the cost over your lifetime with the car. I'd say the only other confusing thread in the forum is how much air goes in a tire.

 

test point,

The official spec for ATF in the ZF 6HP26 is Shell M1375.4. If an ATF you are considering meets that spec, then theoretically you should be good to go. Since both of our Jaguars are long past their warranty periods, I am more than willing to run Mercon SP in them. Ford specified it in their 2005 to 2008 Lincoln Navigators running the very same ZF 6HP26 transmission, it meets the Shell M1375.4 spec, and it has certainly performed as well if not better than the factory fill of Lifeguard 6 in both of our Jaguars....

Do your own research, draw your own conclusions, and choose your replacement ATF accordingly. I remain very happy with my decision and do not hesitate to recommend Mercon SP in any 6HP26 that is now beyond its warranty period....

 

Here you go. I'm not going to argue about it. Just posting the document.

 

Agreed. I've been using MaxLife in mine for five years now without issue. For me, as long as it meets LT71141 that's all that matters for my 5HP24. No use in being suckered in by the dealer (and while your back is turned they're more than likely using the same thing.)

 

ATF and antifreeze. There are two types of opinions: First, use only factory spec... even if it has been discontinued and you have to buy it in 55 gal drums; or the second group wich say you can use more the current products that claim to meet and/or exceed factory specs. Most of the car-smart people I trust fall into the latter group. ZF makes the same transmission for my BMW and the Jag. Yet each manufacturer specs a different fluid. Same for antifreeze. For over six years I've been using the same fluids in each car and I don't worry about it anymore.

 

Right On Gordo! I agree, now lets not get into the Dot5 vs Dot 4 Brake Fluid debate that other forums argue :-). A ZF 6HP26 is a 6HP26 even in a BMW,Hyundia, Navigator,Land Rover or whatever.