When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I've gone through lots of posts here regarding maintenance and issues with the ZF6 transmissions and decided to change the fluid. Though the car is an '03 model, it only has 18k miles on it (documented), and I'm pretty sure the fluid is original. I would imagine after 16 years it's time! This car was truly babied by its previous owner, and I have all his service records, but there is no record of a fluid change.
My question is not which fluid to use or how much. It has to do with the symptom the car is displaying and whether the fluid change will correct it, or if there is another issue present. When pulling to a stop, as at a stop sign, when the car has almost come to the stop, the transmission will pop/bang/slip/jerk/drop (take your pick!) suddenly into gear. It is especially prevalent when coming to a "rolling" stop and then accelerating. Shifting up and down is very smooth otherwise.
Your car exhibits the infamous ZF 6HP26 characteristic known as "The Lurch". Search for it here on the forum and you will discover hours of reading if you are interested in doing so. Some owners have seemingly been able to cure it, other owners have had less success. In any case, a fresh fill of the appropriate ATF is certainly a good idea. The friction modifiers in your factory fill of Lifeguard 6 have long since diminished in their effectiveness. So do an ATF drain-and-fill and let us know if it makes any difference....
You have typical problems with old ZF gearboxes. My ZF5HP24 had the same symptoms and the simple ATF and filter change fixed it.... and in the spirit of while you’re in there, I did the simple Transgo PR valve upgrade.
Well you have a lot of options to consider if you’re doing the transmission filter and ATF flush. Google for kits available. One is the Transgo ZF6 upgrades. Link below.
Not sure if you’re DIYing this but when you pull the sump look at the magnets - if you see chunks of metal, you’ve got more serious problems. Also have a good close look at the valve body for any cracks too in the body casing.
The standard answer is to consider doing a "full" maintenance cycle at this point, involving pan/filter, fluid (check Mercon SP), connector sleeve, bridge and tube seals. Your '03 may have the small Torx pan screws, so upgrade to the larger ones (21 or 23 count). Do the proper refill (temp based) and drive around. A bit later, do a simple drain and refill to get more of the old fluid out. Once done, do a reset of the adaptations to re-adjust the solenoid valve to the characteristics of the new fluid (software procedure). If you feel the car has not visited the dealer in a really long time, maybe consider having them check if you are running the latest software, and consider a reflash if not. Some have said the latest reflash is dated '06, so there is nothing really recent, but you could be running the original code in there. Dealers typically only update based on customer complaints, it is not a routine thing. Do that before the adaptations reset.
Thank you, David. Yes, I'll be doing the deed; just not sure if I want to flush or drain and fill. When you did yours, did you flush or just replace fluid in the pan?
In any case, I'll be replacing the pan/filter and will do an inspection of the magnets and whatever else will be exposed.
The previous owner had a full inspection at the local Jaguar dealer done just before he put it on the market. All it stated was that the transmission was "checked". I need to give them (the dealer) a call and have them check to see whatever updates were done over the years.
Thank you, David. Yes, I'll be doing the deed; just not sure if I want to flush or drain and fill. When you did yours, did you flush or just replace fluid in the pan?
.
I just did the drain and refill ATF which was pumped in and the level check is a constant dribble from the filler plug while engine is running at a certain temperature. Good Youtube video tutorial from the eminent Rev. Sam aka sam1174. You need to do this twice though, seperated apart, as the Torque Converter holds old fluid.
I wouldn’t do a flush as there are horror stories on auto transmission gear boxes that have been flushed out. I’ve never done a flush on either the BMW Z3 or my Jag, so don’t have first hand experience. You probably have the old ZF6 fluid so shouldn’t need to be flushed.
I just did the drain and refill ATF which was pumped in and the level check is a constant dribble from the filler plug while engine is running at a certain temperature. Good Youtube video tutorial from the eminent Rev. Sam aka sam1174. You need to do this twice though, seperated apart, as the Torque Converter holds old fluid.
I wouldn’t do a flush as there are horror stories on auto transmission gear boxes that have been flushed out. I’ve never done a flush on either the BMW Z3 or my Jag, so don’t have first hand experience. You probably have the old ZF6 fluid so shouldn’t need to be flushed.
One question arises: If I go with Mercon SP, as many have recommended, will that mix well enough with the older fluid?
Mercon SP meets the required Shell M1375.4 specs and mixes well with the OEM Lifeguard 6 as a result. We did two Mercon SP drain-and-fills on my wife's 2006 XK8, 5,000 miles apart. That was about 20,000 miles ago. The vehicle is now approaching 120,000 miles and its ZF 6HP26 is performing exactly as designed....
One question arises: If I go with Mercon SP, as many have recommended, will that mix well enough with the older fluid?
Hi Mickey,
Just to add to Jon's reassurance, Ford Motorcraft Mercon SP is chemically identical to ZF Lifeguard 6 except MSP is dyed red, LG6 is honey brown. Just be sure to use genuine Motorcraft Mercon SP since third-party fluids that claim to be compatible with Mercon SP have significantly different properties.
While there are plenty of horror stories about problems after flushing transmission fluid, as far as I know these stories tend to involve the "power flush" machines used by professional transmission shops. I have flushed more than a dozen 6HP26 transmissions by my DIY cooler-line method with zero problems, most recently on an S-Type that had just turned over 200,000 miles and as far as the owner knew, the fluid was original. The transmission had been shifting harshly for quite some time and had recently begun slipping badly. Topping up the fluid with Mercon SP solved the slipping, replacing the pan/filter and flushing the remaining fluid by the cooler lines improved the harsh shifts, and clearing the adaptations and updating the firmware to the latest available (dated 2006) with SDD resolved all remaining shift issues and the transmission operates as new again.
Here's a link to how I do the fluid flush using inexpensive materials from the local hardware store:
If your pan/filter or electrical connector sleeve are not leaking and you don't want to replace them at this time, a fluid flush via the cooler lines or three drains & refills should help your shift problems. If it doesn't resolve them completely, clearing the adaptations and updating the firmware may be required.
This is all wonderful news - thanks to all! And, Don, thanks for the link. I'd read that in another thread and was impressed with your resourcefulness.
I've restored several British cars from the ground up and fairly competent of my ability to tackle most any job. But I've never had any experience with such intricacies that these cars present, and never fooled with software-generated mechanicals. So the trepidation factor is pretty high here!
All of your reassurances are much appreciated, and I'm looking forward to getting this thing done.
As a newbie, I watched all videos and read all I could about changing transmission fluid. My first oil change was not too great. First, I did not realize that I should also do the connector sleeve and replace the seals on the Mechatronics unit. Second, getting the darn oil fill plug back in after you reach the magic 40 deg. C proved not so easy. Burned my hands just about everywhere, and before I know it, I was way past the 40 deg.
I just did the second oil change and this time I was better prepared. Got all the seals for the Mechatronics and, most important, fabricated my own "fill plug tool".
I cut off a piece of 8 mm Allen wrench and epoxied it centered to a 8 mm ratchet wrench. Then I made a second ratchet wrench with a short extension. With the two sections put together and the fill plug at the end, the whole assembly just slips over the exhaust pipe and you have one ratchet hanging down on each side of the exhaust pipe.
You can now use either of the ratchets to align the plug and/or to crank it in and your hands never get close to that darn hot exhaust pipe. This can obviously not be used to break it loose or to tighten to final torque, but it is a great finger saver!
As a newbie, I watched all videos and read all I could about changing transmission fluid. My first oil change was not too great. First, I did not realize that I should also do the connector sleeve and replace the seals on the Mechatronics unit. Second, getting the darn oil fill plug back in after you reach the magic 40 deg. C proved not so easy. Burned my hands just about everywhere, and before I know it, I was way past the 40 deg.
I just did the second oil change and this time I was better prepared. Got all the seals for the Mechatronics and, most important, fabricated my own "fill plug tool".
I cut off a piece of 8 mm Allen wrench and epoxied it centered to a 8 mm ratchet wrench. Then I made a second ratchet wrench with a short extension. With the two sections put together and the fill plug at the end, the whole assembly just slips over the exhaust pipe and you have one ratchet hanging down on each side of the exhaust pipe.
You can now use either of the ratchets to align the plug and/or to crank it in and your hands never get close to that darn hot exhaust pipe. This can obviously not be used to break it loose or to tighten to final torque, but it is a great finger saver!
Great stuff, Nalle - thanks for the tip! You wanna loan those out?
That custom-made tool is indeed a great solution. Should be quicker and much easier on your hands around the exhaust pipe....
The ZF drain-and-fill process does get a bit easier every time you do it. Rick (joycesjag), Wayne (cjd777), and I have done it five times now. Twice on my now-sold 2005 S-Type 3.0, and three times on my wife's 2006 XK8....
I am about to do this again on my 2005 XJR because of a hard fault.
The last time was only about 7,000 miles ago however I did not replace the tubes only the pan and the mech sleeve.
This time all of that will be done as well as new solenoids unless of course I have a serious metal fragment issue.
One member suggested using a wet towel over the exhaust to help prevent burning ones hands and I definitely will try that this time.
I tried the "wet towel" solution before I made my tool. I felt that the towel just blocked my view and made a tight space even tighter. Now I just put the two ratchet pieces together with the fill plug on the end. I slip the whole unit over the pipe from the outside until the inside ratchet hangs down between the transmission and the exhaust pipe. Since you now can work with two hands, alignment is easy. I tried it to put the plug in and take it out about three times with a hot pipe. I never touched the pipe and my hands were far enough from the pipe that I could easily do this without gloves. Always had a hard time working with gloves on!!
Another Transmission Question
)
