So I have another post about changing my tranny fluid, filter and plug sleeve. All went well and car was fine, I thought. I didn't drive it for a few days then Wednesday I go to back it out in the morning (like 50 here) and it lurches searching for reverse while I was reversing out of the garage.

I was concerned and decided to drive it around my block. While sitting at a stop sign it lurched and searched again but in drive. I opted to leave it be, park it and deal with it today.

I decided that maybe I didn't fill it enough (though I followed instructions from various sources). I put her up (level) pulled the fill plug and some fluid streamed out. I plugged it and opted to start over as I was just filling it for the first time. Start, run though the gears, checking temps and the fluid bla bla bla. Didn't really need to add any so I didn't force more in it as it was streaming out as it should at the correct temp.

Dropped her, drove her around the block and she seemed ok. Took her on the road and while doing maybe 40ish I jump on the pedal and she just gasps for air with no gear connection. I back off (only a second) and she engages and drives and shifts fine.

I come home put her up again (which by the way is a PITA), check her again and cant add anymore (FYI I let her cool down to 40.1). Decide to take her for another spin, this time into town (few miles) and during normal to accelerated driving shes fine. Sitting at stop lights, shes fine, coming home at 50 I jump on it and she downshifts fine but I back off as I was shocked it connected.

Thanks for putting up with the read but would this (because shes full of fluid) be something that a re flash would handle ?

When I jumped on her coming home and she was fine I was right by my home so I didn't press it. Plus its 85 here, the A/C was on and Im wondering if just driving her more made the fluid flow through everything better ?

Im also going to take her out in the morning when I get and see as it will be high 50's or 60 at 7 am.

Thoughts guys ? Anyone else deal with this ?

 

Hi John,

Sorry for the delay in responding - I don't know how we missed your post the last few days. A few thoughts come to mind.

1. How did you measure the fluid temperature while filling the transmission and setting the fluid level? If you used an infrared thermometer, I have found the most accurate target to be the fluid coming out of the transmission, not the plastic pan, since it is a poor conductor of heat and does not accurately reflect the temperature of the fluid.

2. The fluid should be dripping out at the correct temp, not streaming out, so you may be overfull.

3. Your Mechatronic/TCM had adapted to your old, worn-out fluid with poor slippage characteristics. Your new fluid has the proper characteristics, so the TCM will have to re-adapt. It helps expedite this process by clearing the adaptations with the Jaguar diagnostic system (IDS/WDS/SDD), and would be even better to also update the firmware to the last version available. I've found this to solve most shifting issues in the 6HP26.

Cheers,

Don



This document has some helpful tips:

Jaguar ZF 6HP26 Troubleshooting Guide


Cheers,

Don

 

One thing worth checking would be where the cable from the selector goes into the transmission. It's fixed to the transmission by two bolts which are known to come loose giving selection problems.

 

Don, outstanding comments, I did use the gun on the pan and it makes more sense to check the fluid. Also it was streaming slightly but definitely not dripping so maybe too much ? I will have to figure out how to reset it as I don't have that equipment but will try to find a shop that can do it. I will open up the fill hole and check the fluid again (up in the air) for temp and flow. Thank you so much.

 

did you use the proper fluid?

 

Actually I had ordered everything for the job but the fluid. I just forgot and went to my local auto parts to buy some ZF but they didnt stock it and needed 3 days to get it (was Sat wouldn't come till Mon) so he referenced it and came up with Mercon SP which was what the YouTube video guy used on his X350 job so I figured that would be fine and that's what I used. Think maybe that might also be an issue ? Wasn't about cheapening out was more about getting done as I had the car up and ready when realizing I forgot to purchase the fluid and needed it done that day due to my business commitments.

 

Honestly don’t know. I read a lot prior to do mine and sucked it up and got the oem stuff. If that fluid meets the requirements and is used in the ford ZF transmissions then you should be fine just a thought.

if it was shifting fine before then you gave new fluid and it’s not happy I assume it needs adaptations reset or the new fluid even if right spec upset the balance in your trans haha. I am getting my adaptations reset on mine after I got my wife’s 06 Range Rover hse to pass inspection at my local rover shop. They said oh you have a 04 jag same thing yes we can reset the adaptations on that.

best of luck to you!

 

John,

As it so happens, Motorcraft Mercon SP is the only fluid available in the U.S. besides ZF Lifeguard 6 that we have been able to confirm is correct for the 6HP26 transmission, so you're good. Mercon SP is made by Shell and the only difference is that it is red while LG6 is amber/brown.

Cheers,

Don

 

There's also Shell Spirax S4 MSP which I think is marketed in Canada but not the US (nor the UK/EU). It has identical viscocities etc to the M.1375.4 specification.

 

This is my own personal opinion for what it's worth. Regarding the Jaguar X350, if the transmission is still shifting nice and smoothly, don't tamper with it. One should really change the oil and filter when shifting problems develop and not before. As the old saying goes: If it ain't broke, don't fix it.

 

Rickkk
Said
This is my own personal opinion for what it's worth. Regarding the Jaguar X350, if the transmission is still shifting nice and smoothly, don't tamper with it. One should really change the oil and filter when shifting problems develop and not before. As the old saying goes: If it ain't broke, don't fix it.Many subscribe to this theory, with great results.I do as well on many things!BUT oil & filters, are the life of the vehicle.Always what i was told as a young man.From the guys that knew how to fix their own cars.The filters on both of mine were leaking a bit when purchased.Nothing terrible, but the first new to me, Jaguar's trans leaking, was not good news.After reading here, i converted to a metal pan, with filter,& Mercon S P fluid.No more leaks, shifts just like before i started, success.

 

So it was having an issue shifting and most on here when I commented on it said its time for filter and fluid..... which I agree with. I contact my Jag dealer last year (I don't drive the car but 1500 miles a year) and had an appointment but had to reschedule and that's when the Jag service advisor told me its not needed, the flash isn't needed and they wont do it. Thanks for the thoughts !

 

For some time now ZF's official advice is that the fluid and filter should be changed every 50,000 to 75,000 miles (presumably severity of use dependent) or eight years, whichever occurs first.

For some reason Jag haven't caught up with that.

 

Service Mgr's thinking?????:
Changing the fluid with filter that's not leaking yet?:
Could open a can of worms, if not done correctly.
Not a oil & filter, basic stuff, lot boy, flunky's job.:
Will tie up my mechanic a good while, (i only have one).
Tell him we don't believe you need it just yet.
When & if it ever starts to squeak, leak, or shift badly, will be soon enough.
Why spend that money on an unneeded job?
Trust our judgment, as well as our ''EXPERIENCE''
We know whats best for your car.

 

I respectfully disagree that one should wait for leaks to develop before flushing the transmission fluid.

I have flushed the fluid in quite a number of ZF 6HP26 gearboxes in X350s, S-Types and late X100s, and in every case the transmission behaved better after the flush, even before doing any computer work. The friction/slippage characteristics of the original fluid deteriorate over time, to the point that the Mechatronic can no longer adapt sufficiently for optimal operation. So regardless of whether fluid is leaking, it really should be changed according to ZF's revised schedule. I recently flushed the fluid on an XJ8 with less than 55K miles and the transmission performance improved noticeably. Of course, all vehicles with 6HP26s have now exceeded ZF's revised 8-year limit regardless of mileage.

I also highly recommend clearing the adaptations and flashing the Mechatronic to the most recent firmware. This has solved harsh shifts every time I've tried it, so it is also likely to prevent or delay the development of harsh shifts if your gearbox hasn't gotten to that point.

Cheers,

Don

 

Today, 01:11 PMDon BwroteI respectfully disagree that one should wait for leaks to develop before flushing the transmission fluid.

Could not agree more
Reread the first line;
Are these the thoughts of why the service mgr refused the job???????????

 

If it ain't broke, don't fix it. It that goes for engine oil change, spark plugs change routine maintenance? Every used Jaguars I purchased, any lubricant oil or any liquid, in the first month, I went ahead and replaced or flushed. This included engine oil, transmission oil, differential oil, brake fluid flush, power steering , coolant system flush etc. My brother works as a master mechanic for one of the biggest Jaguar dealer in the US; and yes, they do change out the transmission oil and filter at 60K miles. His only complaint is the X350 and X358 are super reliable except for the air suspension system. Dealer don't make much $$ on these car repair. He also indicated that any used low miles X350 and X358 on the lot are selling like hot cake at top dollars.

 

The same things that ANYONE with any sense, does this to ALL their VEHICLES soon after their purchase!!!
I was wondering why a dealer would not want the job, in my first post.
They all seemed about as absurd as the idea of not wanting the work!!!

 

HAHAHAHAHA !!!!! So I decide to go to the local Jaguar/RR mechanic I didn't have a lot of luck with then I had my RR because they really are the only place close. Its been a couple years since I've been there and they have never worked on the Jag. They are nice and personable. On the phone Friday I xxplained what was happening (reaching for reverse, searching for a gear while at a stop light and not downshifting if you jump on it) before I changed the fluid, recommended by many if not all Jaguar forum members. I did this and still have the issue as mentioned. I have been repeatedly told to get the trans adaptations updated. They said, yep, no problem $136.00. So I drop it off, explain again everything done previously to bringing it in and he says ok.

I just got there call that the trans is bad and it will need a new one or rebuild it. Claims when it is in reverse and rolling then searches for a gear is slipping. When your at a light and its searching for a lower gear, its slipping and when you jump on it while driving and it just searches its slipping so because its slipping they cannot update the adaptations and I need a trans.

Isn't updating the adaptions supposed to fix this issue ? He said no because the trans is slipping. WTF (<-not typing the bad words) !

So do I find a ZF tranny specialist and take it to them ? I saw virtually NO metal in the pan when I replaced the filter, it was silky smooth so I don't think it needs a trans, I think they don't want to do it. Why would you agree it needed the update based on what I said on Friday then when you have the car on Tuesday its a completely different story.

I love Jaguars and my car...... but I hate trying to find a good mechanic to help with the stuff I cant do.

Thoughts guys ?