This was done to (I hope) get rid of the 'chirp', based on the 60,000 on the clock, and because common sense says nothing lasts forever (or even 60k) and because even ZF concedes that it could be beneficial. And then there was the Jaguar TSB about the (now unobtainable) ZF additive. The fluid chosen was, on the basis of Ford's use of the ZF 6HP26, their use of their own brand, Mercon SP (which spec's look almost identical), comments from the Forum, and the fact that Mercon SP costs $8 a quart. I'll report back on the presence or absence of chirp when I have some miles added and I'll 'fess up should the planet stop turning and becomes a satellite of Jupiter from using something other than Lifeguard 6.
This is more about what is in store if you attempt this in your driveway / on the floor under axles stands. I will readily admit to being past my prime, but the car was at a friend's garage and on a lift, and there were two of us with just about any tool known to man, telescoping drain pan, gear pumps, you name it, and it was still a hard job that took from 10 am to 9:30 pm with a considerable amount of dripped fluid. The job was to change the fluid, change the cable sleeve, and change the Mechatronic box seal. The total amount of oil drained (and later replaced) was 7.6 quarts. Before doing anything by way of draining, free the filler plug. This has a heft hex socket, but there is no clearance for any combination of sockets or extensions, so I had to use a small wrench on the hex, plus and extension pipe, and both tension and rap the pipe wiyth a hammer. This is supposed to have 26 ft lb on it, and it does! By the way, you can't actually see the hole the plug goes into, because of the exhaust pipe. This becomes even more envigorating later on when the exhauts pipe is burning through your glove.
1) The 2005 XK8 is not one of the "later models" said to have T40 machine screws. Nope, T27 it was. I forget my more adjustable impact wrench, so used my friend's on LOW. The first few released their corroded threads, but then: ping! Broken T27, with stub left in screw head. I was hammering away at the edge of the head when - miracle - the stub fell out. New T27 bought at Autozone, but with a 1/4" drive. Friend lowered air pressure to 55 PSI and no further problems overcoming the thread corrosion. New screws come with T40, not that you need it to torque up the screws in the first place. Good advice from You-Tube and elsewhere, the tranny fluid never stops draining. Never. Release all the screws except the three nearest the engine and two at the back, let the back end down and drain away more! Eventually, bite the bullet, remove the screwsand try not to spatter too much on your clothes.
Removed cable cap lock, dropped latch. Now hear this: not all sleeves are identical even when they look identical, and as there is almost no access to the cable connector, and even less purchase to push or pull on it, when we came to installing the new sleeve it wouldn't go in far enough. Eventually, I swapped the O rings over and re-used the original. Watch what the ZF guys say about touching the cable connector pins. You discharge static into that wiring and the pain (and expense) will reach the infinite. The latch inside the transmission would not go back up, even when we had the Mechatronic on the bench. It seems that the sleeve has to push hard against two small exposed parts of the latch spring blade. As said, even with the thing on the bench it still took over an hour to figure what had to happen, but as I said, pushing on whilst off the car is one thing, doing it reaching over the transmission mount is something else.
There is a heat shield in the way of the filler plug - replacement item in hand, by the way - and the 8 mm screws are blocked considerably by the exhaust pipe. A call was made to my friend's wife, for a pair of small hands, when replacing these.

Moving on... the Mechatronic screws were easy enough, there being no oxide involved, but be ready for 1) a bunch more fluid and 2) the thing weighs quite a few pounds. Pulled out the old square seal, reached for the new one. Oops! This one has a plastic flag on one side and a projection between the two channels. Get out Dremel. Clean and install seal. The two of us together could not reposition the Mechatronic, mainly due to aligning hole and the weight. Move jacking platform into position, get scissor jack, my pal now comes up with a brilliant idea: use a fabric buffing wheel on top of the jack to protect the Mechatronic. Remember to position the emergency release mechanism before inserting and torquing screws (per pattern), depending whether you have E-shift or J-gate.
Assuming the cable connector sleeve is in place and and locked inside and out, install the new pan / filter and torque per ZF pattern. Check that the drain plug is torqued correctly. Mine was, but don't assume. Pump a couple of quarts (if you are lucky) into the pan before it comes back out at you. Start the car and move from park to R and D, whilst hollering to you companion to resume pumping. This is necessary because I was sitting 7 ft up in the car, but the same sort of fun goes on if you were to be lying underneath. Keep and eye on the temperature with an IR scanner. The fluid you are installing is not at the required 40 C until it has been circulating for a while. Sooner or later, you will be at 40 C with a stream of fluid dribbling out. The engine has to be left running to avoid a flood of fluid! Also, so that you can get nicely warmed up trying to insert and do up the filler plug. Your glove (leather, but fluid soaked) will smoke, so be ready. The impossible task of putting 26 Ft Lb on this can now take place. Call upon some obliging lady when the exhaust pipe has cooled, and reinstall the shield.
Now even though I did see with my own eyes someone do this on You-Tube, I can't remember what model it was, but on the Jag XK I would have a problem deciding whether the guy should be recognized as a hero or placed in the hands of a professional. Shrink, that is.
If I have missed anything, ask away, but although I wouldn't have done this project if I didn't think it would help (the oil was dark and slightly pungent) I also wouldn't have done it if I had known what I was in for. On the other hand, I can see this becoming a $2 grand job at the Jag dealer, so maybe it's just as well I didn't know. On the floor in your garage? Forget it!

 

This reads like a Robert Louis Stevenson adventure tale, to be read on a stormy night propped up on pillows in a four-poster bed with a cup of cocoa on the nightstand. You've covered the details quite thoroughly, and thanks for letting us off the hook with your admonition not to try this at home.

You leave me not with a question not so much mechanical as psychological: how has this ordeal impacted your relationship with your cat? Do you feel any differently as you are traversing the gears over hills and valleys? I should expect a profound sense of mutual appreciation and renewed partnership.

Very well done!

 

Wow nice write up. What exactly does/is a mechatronic ? I don't recognize that term.

Thanks
John

 

Thank you very much gentlemen for your comments - and for the patience to read the entire gory story. As long as this gives someone pause to consider how badly they want to do this job, and whether they are fully equipped, I will have done what I set out to do.
The Mechatronic unit is ZF's term for a highly machined block, the lower part of the transmission, that is responsible, by way of a number of solenoid valves, to apply hydraulic pressure to the several clutches involved in shifting gears. The brain lies outside the transmission and communicates by way of a multi-conductor cable connector, whose leak proof integrity is the duty of the sleeve mentioned. The Mechatronic unit also conducts what I assume is return fluid by way of the dual box-shaped rubber 'gasket', also mentioned as a potential failure point beyond 60,000.

 

As mentioned, the 6HP26 is effectively the same transmission that Ford puts in lots of its vehicles, especially the F150 pick up and its derivatives. The Ford service interval is at 150k miles with a drain and refill only.

I had my fluid changed at the local Ford Store. They charged $7.65 ea. for six quarts of Mercon SP fluid and $50 labor. That replaced 60% of the 100k mile fluid. A couple thousand miles later I had them do it again which resulted in approximately 86% of the fluid being replaced. Total cost was about $250.

About 2 hours total in the waiting room reading a book. No burned fingers.

 

The X100 filler is in such a PITA position, I wouldn't trust any garage to do this by the book and get it right.

 

The feedback with regard to Ford and the 6HP26 (albeit without changing the connector sleeve or the Mechatronic seal etc) shows the difference between telling the design engineers to allow for fluid changes on the one hand, and assuming that wishful thinking is all that is needed and providing almost no access and no means of easily checking levels, on the other! It is actually rather disgraceful, when you think about it, for a company with the name recognition of Jaguar to buy into this 'sealed for life' nonsense. I appreciated the Ford input earlier, because the Mercon SP alternative wouldn't have otherwise occurred to me, not knowing that anyone except BMW and Jag used the 6HP, much less having their own brand name of tranny fluid.

 

There are several manufacturers besides BMW and Jaguar who use the 6HP26/28 gearbox. They include Aston Martin, Bentley, Hyundai, Kia, Maserati, Rolls Royce and Ford.

Bear in mind that the fluid specification for each of these different applications may vary depending on torque input and other factors.

 

Isn't it just great when what it says in the workshop manual gets translated into real life. Great write-up, thanks. I'm just contemplating the job...

 

I feel that I have benefited often enough from the experience of others to share whenever I think it might be helpful. (Not quite dating back to early days in Surbiton,during the war, Oddjob)
The comment from NBCat about different grades of fluid being expected with different engine torques is interesting. I hope that the reality isn't that Ford has created a dumbed-down version of Lifeguard 6 in its Mercon SP, otherwise my entire strategy just went out the window!
I can imagine that gear ratios will change from car model to car model, but is there evidence that Jag or, say, BMW changes fluid when it is dealing with a higher HP engine, such as an M5 versus one of the more normal 325 series, while using the same 6HP26 box, for example?
Is the XKR equipped with a different box, or is it equipped with the same box with different fluid? When I looked at ZF's web site they certainly cite various Lifeguard fluids, but they seemed to be for different boxes. It would be good to see some references / citations, so that I can go back to sleeping at night

 

Thanks for the great story, AtlastaJag1

Despite your warnings, I really do have to get this and the replacement pressure valve jobs done as PM. I've been walking past the drum of fluid for the best part of this year pretending not to notice it.

Member Scardini1 did the Mercon swop. Here's his story, which might help the insomnia:
https://www.jaguarforums.com/forum/x...6/#post1274872

LOL ...and the techs in the pictures always seem to have perfectly manicured hands

Mike

 

As far as I know, the torque rating is the "26" part of "6HP26", assigned by ZF. From memory, "26" is just a number, it has no unit, and is used for comparison with other ZF models. The higher the number, the higher the torque rating. And yes, the 4.2 XKR, supercharged, with the extra power/torque has the same box and fluid.

I have not done the research personally, but typically, transmissions call for fluid matching a certain specification. In the case of the 6HP26, more than one fluid meets that spec: Jaguar, LifeGuard6 and Mercon SP. For argument's sake, I suppose there are BMW or Bentley branded versions of this fluid as well.

Maybe someone should call the Bentley dealership to check if they can beat the Ford price on this fluid...

 

A point of reference, I had this done at an Independent Jaguar specialist in July 2016:
Total was $860.14
Parts = 474 and Labor = 386.09
Oil Pan Kit = 265.45
Trans Fluid = 195
AT Plug Adapter = 13.60

 

The valve body with the integral TCM is known in the automotive industry as a 'MECHATRONICS' (Mechanical/Electronics)

You will recognize the term in the future as the electronics become more prevalent.

bob

 

Thank you for a great story. A commoncomplaint I hear with this fluid change service is burning hands. I hear you. Icompleted the task using floor jacks and insured my '99 XK8 was level. Time forme was not a factor so I decided to remove the exhaust. Easy task. The clampsystem used is fantastic. All the clearance I needed, clear view ofthe filler plug ( loosened before draining the pan) as well as ease of panremoval. Refill was much easier. While I was at it I replaced the hipressure valve in the valve body by Trans Go. A year later I'm stillnursing my weak ZF trans. ( reason for initial service) A complete overhaul isin the future. Maybe another year. Rich

 

I did mine on stands on the drive way, had no issues. Gave each screw a squirt with WD40 the day before and gave each a tap with a punch/hammer before I tried to remove. Dont use an impact driver as the torx bit is too small to hold in the screw recess, use a ratchet only. To remove the fill plug, get a long series allen key and cut off a section to allow it to fit in the gap. Make sure its fully in the recess and use a spanner or tube for leverage. As for the fill procedure you dont need to be so **** as the ZF procedure states. I mean just think about it, the oil level sloshes about in the box with changes in incline, turning, accelerating, braking etc. Just make sure its been running for 10 minutes and fill to overflowing, job done , no problem.

 

Ok - so a couple of questions:

1, what is the recommended change interval - 150K?

2. with regard to the drain and refill only mentioned above - isn't there a filter built into the bottom of the pan that needs to be replaced to really do this right?

Thanks in advance for tolerating the novice questions......

 

Ford's change interval is 150k miles. The use of the ZF6HP26 in Ford vehicles hasn't been around long enough to create the an explosion of complaints. On the other hand, after 4-5 years there has not been a lot of noise on the subject on the forums.

If you have ever changed a filter in a transmission you found that it is only a 'screen' filter intended to stop chunks. Smaller wear steel particles are captured by the magnets in the pan.

I changed my 86% of my ATF at 100k miles rather than the 150k.

I will probably spring for the 'Full Monty' at 150k.

My opinion of the less than outstanding reputation of ZF's in earlier versions of the XK cars is that there were more problems with the mechanical valve body that failure of the ATF. I can accept that totally ignoring the ATF could/probably contributed to valve body wear but only after an extended level of miles.

 

A very common ZF recommendation has been 10 YEARS.

bob

 

You can indeed sleep well now that Mercon SP is circulating inside your ZF rather than Lifeguard 6. Many of us have been running our 6HP26 units using Mercon SP for years with zero issues. In fact, I believe my 2005 S-Type's ZF performs more smoothly and predictably now at 96,600 miles than it did at 18,000 miles when I purchased it with its factory fill of Lifeguard 6 in December 2008. We've done two Mercon SP drain-and-fills on it - the first in early November 2014 and the second in late October 2015. I hope I'm done with this particular ZF for the remainder of the time I own the vehicle....