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.
Over the last couple of weeks my car, which has the later 6 speed ZF gear box has randomly thrown a Gear Box Fault warning when driving. The car drives and shifts fine. When the warning appears it goes in some kind of limp home mode. If you stop and restart the car all is fine. It can drive hundred or more miles before this happens.
Do you think this is the start of something serious or a gremlin?
My advice is not to ignore any warnings related to the gearbox in our cars. It could be the start of something serious and costs can sky rocket if the gearbox goes out as there are very few people with the skills to DIY home repair the internals of a ZF6 unit. You could be looking at GBP1000+ for a gearbox repair at a professional transmission garage.
So first question - can you read the DTCs esp. in the transmission module? This takes more than the simple OBD2 reader. If you can't, I suggest a trip to a capable garage with the software and they should read the DTCs for a small fee. Post the results here.
Second question - are there any other symptoms such as an occasional jerky pull away when cold, or when hot stuttering down shifting esp. 2-1-stop. Is reverse dependable or does it clunk into gear? Read up on the infamous ZF "The Lurch" - Jaguar S-Type ZF Gearbox Lurch fault
Third question - when was the ATF gearbox oil and filter change last done? That can be home DIY-ed and is relatively in-expensive. That tends to fix most things as low level or old ATF can cause alot of issues. Depending on your home wrenching skill levels you may even go for some home DIY modifications that pre-empt most common problems. Transgo is my go to place for things to consider. Link below. https://transgo.com/products/zf6hp19-26-32/
Not to scare you, but I wouldn't just consider this a gremlin. BTW I've got the ZF5HP24, so don't have hands on experience with our ZF6 unit but I am more than familiar with auto gearboxes.
Whilst it is best not to ignore the message as could be something serious, don't be too scared as it could also be something simple like a dodgy wheel speed sensor.
I'd say considering the cost of diagnostics at a shop, get your own handheld Jaguar/Land Rover code reader (Foxwell, iCarsoft, etc.) instead ($150?). And no, a cheap generic OBDII tool will not do as you need to read the proprietary JLR codes. Codes are easy to search and are a great starting point. These gearboxes are generally very reliable, but there are issues that can develop over time, ranging from a cheap brake switch to a pricey refurb valve body. "Blind" starting point is usually a comprehensive maintenance procedure (fluid, pan/filter, connector sleeve, tube and bridge seals), quickly followed by a further flush/refill. Most trust the cheaper Mercon SP as an alternative to the Lifeguard 6. If you are bored and looking to get something done, check all 4 wheel bearings are tight, and check the ABS reluctor ring is still solid with the axle, especially rear, left side.
1. I have scanned the car today using SDD and there are no transmission DTCs, just an error regarding adaptive cruise control (which works fine for me).
2. The transmission does not display any of the typical issues, no issues reversing, no harsh gear changes and absolutely no lurch. The only issues are occasionally there is the squawk (see next point - this was worse before) and since the transmission fluid change I do have the perception that car "lags" between changing gears and seems resistant to put power to the ground.
3. Two years ago I had the transmission fluid changed by a local garage they used the official ZF lifesaver kit with the sump filter, etc. The car squawked a lot before this, but felt more responsive.
4. I have no idea how old the battery is and I have had this car for nearly two years. I did try and look up numbers on it, but uncovered nothing meaningful.
One theory of mine / perception (could be nonsense) is that the Gearbox Fault error is most likely to arise when throwing the car around bends and going over bumps. It has not appeared when cruising on the motorway, but has when going over a humpback bridge, over speed bumps and on a bumpy bendy seaside road.
Please let me know if any of these leads to any ideas.
1. I have scanned the car today using SDD and there are no transmission DTCs, just an error regarding adaptive cruise control (which works fine for me).
As per the electrical guide, the adaptive cruise control is also on the CAN bus so the 2 are not necessarily independent. The module has a reputation of being susceptible to corrosion (I believe it is located in the front bumper).
I'd say double check the bearings and reluctor rings, especially on the rear.
Altogether, you might have to take SDD with you and scan when the error occurs. Not sure what survives once you shut the engine off...
One theory of mine / perception (could be nonsense) is that the Gearbox Fault error is most likely to arise when throwing the car around bends and going over bumps. It has not appeared when cruising on the motorway, but has when going over a humpback bridge, over speed bumps and on a bumpy bendy seaside road.
Could that not be indicative of low trans fluid level?
Hello good people:
I'm joining this thread with my new (to me) 2004 XK8 with 51,000 miles. It has symptoms of "the lurch" when upshifting from 1 to 2, but no other gears nor downshifts. I would like to change the tranny fluid. So pardon my ignorance, do I have a ZF6HP26 tranny? What type of fluid should I stockpile? Should I drop the pan and swap filters, or just drain and fill repeatedly? On my Mercedes there is a torque converter drain plug, is there such a thing on the Jag? I have a lift so access from below is no problem. Will I get in trouble if I fill with fluid different than OEM (assuming it is the original juice)? Finally, should I put the same fluid in my power steering or just use power steering fluid? Thank you in advance for any advice you may have and stay healthy and roadworthy!
The filter IS the pan, or the pan IS the filter how ever you want to look at it. Use Mercon SP made by/for FoMoCo, I found it at a good price on amazon by the case of 12. No converter drain plug that I know of. My '03 (6 speed same as yours) is butter smooth after one drain, filter and fill. I'll do another later. TM
Hey hey, thanks for that helpful reply. I can get a case of Mercon SP on Amazon today. So before I start should I buy the filter/pan? I forget where I read about the torx pan bolts; should I get a set of T40 screws to replace the OEM T27 bolts? It seems like the OEM are a pain in the butt or can I reuse them? rock auto beck /arnley filter pan?
Yes, you have the ZF 6HP26 transmission. You definitely want the Torx T-40 pan bolts. Your 2004 model may already have them. Have you checked?
The first time we serviced my wife's 2006 XK8's ZF, we installed a new pan, a new sleeve, and almost 7 litres of OEM Lifeguard 6 ATF. That was in July 2013 at 67,000 miles. Her car already had the T-40 bolts. I purchased 4 extra T-40 bolts in case any of the factory bolts stripped on us. None did and I still have those 4 spares....
We switched her car to Mercon SP ATF in April 2016 at 99,000 miles. We did three separate ATF drain-and-fills (no pan removal) between April 2016 and November 2016 so the fluid in her ZF right now is probably 85% to 90% Mercon SP with a small amount of ZF Lifeguard 6 still circulating around in there. Mercon SP meets the required Shell M1375.4 specs and I believe the only difference between Mercon SP and Lifeguard 6 is the color (Mercon SP is red, Lifeguard 6 is amber) and the cost. The car now has 120,700 miles on it and the ZF is performing exactly as designed....
Yes, that would be the pan/filter. I believe I got mine at rock auto. I did get the wrong filter the first time that isn't a pan. Meant to write them about that. I only boogered up one stubborn screw head but it was usable. It's a messy job that will make ya cuss but worth saving the trans. Life time lubrication my hiney!!
The life time ends when your transmission fails!!
Changed the fluid, attached is the procedure I followed with pictures of major steps. I usted T30 not T40 torx and filled the tranny from above using gravity, otherwise pretty much what everyone suggests here.
07-23-2020, 03:44 AM
XKR 4.2 Gear Box Fault Warning
