At just over 74,000 miles I had my transmission fluid changed. I wanna say I was experiencing a rough 1-2 and a delay in reserve which prompted me to worry about the trans and do all my research, naturally I decided on a fluid change. I also had my shop replace the rubber mechatronics sleeves that tend to wear out.
Fast forward to now 75,500 miles I am getting rough 1-2 shifts again (probably worse) and still that delay in reverse (that never went away actually) 1-2 isn't the only up-shift that I can feel but really 1-2 is what can be pretty bad!

I know a lot complain of bad DOWN shifting eg: 2-1 in these transmissions but I can certainly say mine seems to be up-shifting, particularly that 1-2.
I'm getting worried here and definitely kicking myself for not doing this service when I first got the Jag over a year ago at just over 60k. I suppose I was just really enjoying the car at that time.. not to mention general lack of knowledge on the ZF 6hp26.

Seeking advice, has anyone had similar experiences? Would love to keep this car for years to come but transmission issues seem like a surefire way for that not to happen

 

Hi Connor,

My first question is whether the fluid was completely replaced (flushed) or did the shop simply drain via the drain plug, replace the Mechatronic seals and pan and refill. If so, only about half of your old fluid was replaced.

Second, was the correct fluid used? The only fluids commonly available in the U.S. that are correct for the 6HP26 are ZF Lifeguard 6 and Ford Motorcraft Mercon SP, both of which meet the correct standard, Shell M1375.4. Any other fluid may have incorrect properties and may not perform properly, including any of several that claim to meet M1375.4 but have viscosities and other properties that are significantly different from LG6/MSP.

Harsh shifts can often be resolved by having the Mechatronic adaptations cleared and the firmware updated to the last version (c. 2006). It would be worth finding a local shop with this capability. I have updated several 6HP26s using Jaguar Land Rover Symptom Driven Diagnostics (JLR SDD) v.130.03, which has the full updated calibration files.

The last thing I would suggest is to have the screws on the gear selector cable bracket checked. This bracket is affixed to the left side of the gearbox with two screws known to loosen and even fall out. When they loosen it can become difficult to precisely select Reverse or other gears.

Please keep us informed!

Cheers,

Don

 

So I recently had my transmission fluid change at just over 74K miles along with "updating" the software. I also had them change all the mechatronics sealing sleeves as I learned those tend to wear in my research on these ZF's. So fast forward to now 75,697K miles I am having transmission problems once again.
My main symptoms being rough 1-2 Upshift and a Delay when shifting to reverse. I want to say at times I can definitely feel the 2-3 but its definitely that 1-2 that can be pretty bad! It's also worth mentioning these are the same issues I was originally having, minus the "LURCH" but I'm not sure because I haven't tried to make it do that again. Also the delay never went away, I was starting to think it was normal as everything else was working fine for a little.

So i'm getting worried, I do daily drive this car for the time being. In that BMW Logic7 article often referenced on here it claims 99% of transmission issues in these ZF's are a result of valve body fluid pressure loss.

My question is what am I looking at here? Replacing all the solenoids ? Replacing all the solenoids + that "Sonax Zip Kit" ? Valve body or worse..?
I video I commonly referenced in my research on all this fun stuff was this:

ZF 6HP 6 Speed Auto Transmission Troubleshooting

He mentions hes never had to replace a valve body. Only the Solenoids and mechatronics sleeves. With that said the article mentions "replacing just solenoids without rebuilding valve body, where accumulators/pistons always go bad after 60-70k, will not get you perfect results, but might improve shifting quality. Remember-cheap people usually pay twice (no offense)."

Seeking any kind of advice here. Anyone with experience on these transmissions or anyone who has experienced similar issues please point me in the right direction here! Thanks!

I love this car and I would love to drive it for years to come but transmission issues seem like an easy way for that not to happen..

 

I don't have an answer and Im sure someone here will. I had all your issues pre fluid change, did that (no update of software) and still have the issues. Took it to a couple "jaguar" specialists only to be told I need a new trans. Thing is Don and Moderator here doesn't think it does. My fluid change used different fluid then the ZF labeled (same product but different color, difference name, half the cost) and Don thinks I need to flush out all the only fluid so its got 95% new fluid. See as he will say, you had the fluid changed its only available to be changed and that leaves old fluid in the torque converter, once the computer realizes its not all the same it wont fix itself.

Ill shuddup now I have 80K on mine when this happened so were in the same boat, same issues and hopefully same thing can fix it. I have not had time to do the full flush but have everything just too busy so I hope Don chimes in and can offer some help.

 

Hi Connor,

I have merged your two threads. Please do not start any new threads on this topic since it creates confusion and duplicate effort on the part of those who want to help.

In your first post you did not mention that the Mechatronic firmware had been updated, but in your second post you do. Do you have any details on what was done, such as what system was used (Jaguar Land Rover Symptom Driven Diagnostics (JLR SDD))?

Also, as I asked before, was the fluid completely replaced (flushed), or did they only drain the pan prior to removing it then refill and set the level? What fluid was used for the refill?

Have you had the vehicle scanned by SDD or another system capable of reading the proprietary Jaguar diagnostic trouble codes (DTCs)?

Have you checked the screws that secure the gearshift cable bracket to the left side of the gearbox as I suggested before?

Cheers,

Don

 

Hello Don, sorry I thought my first post didn't work as It never showed up in here so I made another.

So when I took the car in I told them to change the fluid, update the software, and replace those sleeves. Not sure what exact system was used for the update but he mentioned how they can do it because they have the genuine jaguar tool.

Here was the work done in their words...

I notice they didn't list the software update but we for sure spoke about it in person..

Thanks Don.

 

Hi Connor,

I'm not sure your image made it - I can't view it in my browser, anyway. You might try to upload it again.

It would be worth asking the shop if they managed to update the firmware since it is apparently not listed on their report. Perhaps they forgot or were not successful?

Cheers,

Don

 

Okay I'll make sure to give them a call to find out. Here is that shop report again hopefully it works now

 

This is just for perspective, and not meant to belittle any of the efforts people do to be kind to the 6HP26 transmission. For the 2 X350's I have had, the first I drove from 107k miles to 177k, and the current one purchased with 89k a year ago currently at 102k miles, I have been lucky, in that I have had no transmission issues. When I say no issues, I mean none at all. No harsh shifts, no "lurch" no delays, perfect downshifting when demanded by throttle application, and perfect response to manual J-Gate shifts (mostly downshifts to save braking on downhill runs, or when driving in stop and roll traffic.

As I said, this is not to do the superior dance, it's more curiosity about how some cars have many issues, and others don't. I do not think it has anything to do with driving habits (except in extreme cases where people beat on the car, which I don't think is too common with these vehicles - maybe a few cases with younger, crazier types, lol) So, if its not the way the car is driven, maintained etc., what then explains the inconsistent transmission behavior. I know that ZF's current transmission; the 8HP is used in everything from Bentley's to BMW's with output shafts for AWD and is considered one of the greatest auto boxes in the world. Fast shifts and superb performance. The 6HP is a predecessor to it, and while it's not as sophisticated, surely it has elements that are similar.

Both of my cars have had identical transmission performance. The only time it ever screws up is when you fake it out by changing up accelerating, letting off and braking to stabbing the throttle again. In these cases, it will hold the lower gear as if saying: "until you figure out of your going or not, I'll just stay in this gear" I also LOVE the way it interacts with yaw control, when coming out of a turn in a lower gear -that it holds the gear (this time exactly as it should) instead of ruthlessly dropping imto the highest gear available for your road speed. The two critiques I have for it even when working as designed are that it does not shift very fast, ever, under any circumstances, and thet "Sport" mode (or whatever "S" signifies" does little more than hold gears a tad longer. That's partly Jaguars fault I suspect in their specifications for the mode were very conservative. While a wish list that would include stiffer shock damping, faster throttle response, less steering assist etc. is all pie-in-the-sky, getting this transmission to really change behavior should have really been achievable, I have always believed. Ah well, what might have been. Things like the suspension lowering 15mm when travveling at 100 MPH (160 KPH) after 8 seconds, then raising back up when speed drops to 88 MPH for 8 or more seconds (they MUST have been "Back to the Future Fans) - this would be SO cool to manually perform with a dash switch or at least change the number to something usable like 75 or 80 mph.

Lastly for critics of the J-Gate, I will say that sure, it's not perfect, but holds it's own compared to Tiptronic "Up/Down" shifters that need a display to tell you which gear you are in. I particularly like the left/right horizontal 6th to 5th shift, and vertical 5th though 2nd. I use the 6th to 5th all the time to drop 5 mph without applying brakes at all, which keeps me off the slow car ahead when going down hill (odds are that car has less overdrive) I don't use the J-Gate to hold gears on acceleration, but it's perfect for controlling speed when cruising to avoid hitting the brake constantly.

I wish I knew why there are trouble prone transmissions out there, but its a true mystery. They ones that have issues are notoriously tricky to resolve from all the stories we have seen. I almost wonder if its a BAD idea to do a fluid swap on mine, since it does open a can of worm(gears). If I do, it will be LifeGuard 6 all the way, and VERY precise filling/temp monitoring. That and quite a few beads of sweat on the brow, clenched jaws along the way.

Best of luck to Connor Miller and John Fox - I hope you get everything squared away, I would not want to be dealing with the issues you are having. While I believe servicing these transmissions is appropriate, TCM adaptations/reflash, firmware updates, fill procedures based on temperatures, etc. NOT my idea of fun times.

 

Very interesting write up John, that's fascinating that you haven't had to touch the transmission at all, I wish I had your luck with that! Are you aware of any servicing on it before by the previous owner? Despite when people are experiencing problems with these transmissions I see the general consensus is they are well made. As you said definitely not the quickest shifting but I'd say it fits the character of these Jags. I'm not well versed on those 8hp's but I believe it as I see they been in use for a decade now.

I just hope I can get this whole thing sorted out and not have to worry about it anymore as I hope to get to take this car to 100K + too eventually.
Thanks John !

 

You bet! Just follow best practices and the immense experience of forum members, and with a bit of luck you will get there!

It sounds like your doing the right things so far. I can say with some certainty that the previous owner did no transmission services. The car was so sorted out, that other than brakes, coolant services and ridiculous oil change intervals he had little else to do. ( one oil change at 1700 miles, as he had other cars and only put 4k miles a year on the car)

The oil would stay amber for over 1000 miles when I first got it. It's not all a bowl of cherries. If only I realized how much salt they use in the aptly named "rust belt" - I will never buy another car in Ohio. Every steel bolt holding the plastic panels under the car was either rusted on, or broken (splash tray under engine.

Ahh well, it's still a wonderful car, and I'm happy to have it.

Best wishes sorting out the transmission.

 

Blairware wrote

I will never buy another car in Ohio. Every steel bolt holding the plastic panels under the car was either rusted on, or broken (splash tray under engine.

Spraying with the old A T F, or using new in your oil can on those bolts, a day or two before helps a lot.

 

Blairware,

That statement brought back a memory. A few years ago the son of a friend and neighbor ran his Isuzu Rodeo low on oil and ruined the engine. So his father found a donor vehicle in Ohio. The body and interior looked nearly new, and it ran great. So I pulled the ruined engine out of their Rodeo in about 5 hours working methodically and bagging and labeling parts.

Then I started on the donor vehicle from Ohio. The first time I crawled underneath, I realized the entire undercarriage was covered in rust that in places was 1/4 inch thick. Not a single fastener would yield to penetrant, heat or brute force, and a lot of the fasteners were grade 10, so trying to drill them took forever and broke several bits. It was a 4WD model and the front axle had to come down in order to remove the engine because the oil sump & pump were nestled closely around the axle. I finally had to use my Sawzall to cut through the axle, braces and other components around the transfer case. No fun at all. If I'd had an acetylene torch I might have just torched the entire vehicle.

Ever since, it's been a running joke with my friend whenever one of his vehicles needs work, that we should find a good donor vehicle from Ohio.

Cheers,

Don