Hello everyone,

this is my first post here and it will take few words before I will explain my situation, so please bear with me. : -) I have spend quite a lot of time reading posts here, but I was unable to find exactly what I was looking for.
Car is XJ8 3.2 1998 (model year first half of 1998, so before "update"). It has now 62k miles (real). Transmission fluid and filter was changed around 7k miles and 5 years ago by previous owner (have receit).
So, now the problem. I bought the car 1000 miles ago and few days ago, transmission fault appeared during kickdown, transmission stucked in fourth afterwards. After shutting engine down and starting again, all was well. No error codes when I connected it to OBD reader afterwards. Tried kickdown, no problem. So first question.
When shifting from anything to D or from D to anything, the car do make a small "thud" or kick, but in my other cars, I wouldn't pay it any attention, as it is very small. There is no "thud" from N to R, P to R and from D to R the "thud" is only because the D is disengaged. D to N makes the same small "thud". So, how big exactly the kick from shiffting have to be to indicate problem with drum? Or if there is any "thud" at all, is it wrong?
And the thing I was unable to find. When I go uphill and have the pedal pressed around halfway down (not sure how much, just guessing) for at least 10 seconds (again, may be minus few seconds). Afterwards I press it even more, but still not into kickdown and hold it there for a few seconds (2-3 is enough). Car downshifts by one gear, but when I release the pedal, even fully, the car stays at the same gear for nearly 10 seconds before upshifting again. Nothing I do can change that. I looked into manual and literature for transmission programs to see, if there is some mode for this behaviour (climbing or something that will explain it) but no luck. Anyone experienced something like that, or is it another symptom of failing transmission?
As of now, the next course of action checking the fluid level and connectors. And then waiting till it fails completely or is it more economical to go to transmission specialist for assessment of the situation?
Thank you all for keeping with me and also thanks for any ideas. : -)

 

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Your problem does not sound like the common A drum failure. Are you using sport mode or normal? I am not well informed on the transmission operation, but I think the torque converter locks when in 5th above a certain speed and unlocks when you down shift or drop speed. Some one will clarify this, I hope.
It would be a good idea to change the transmission fluid and filter, then see how it behaves. Replacing the main pressure valve in the forward valve body would be a good idea at the same time.

 

I had a previous car with problems with auto downshift from 5th to 4th. After a lot of diagnostics the issue was that the Transmission Control Module was not releasing the torque converter lockup on commanded down shifts. A replacement from a JY was plug-n-play and resolved it.

 

Hi Myskoc,

Welcome to the forum!

The very first thing you should do is to check the transmission fluid level and condition, since low or burnt fluid is a common cause of shifting problems. The car doesn't have that many miles on the fluid, but since it's been 5 years, who knows what the level is if, for example, there is a slow leak in the transmission pan seal.

You never want to just "wait till the transmission fails," since rebuilding or replacing a transmission is one of the most costly repairs you can face. A little preventative maintenance may be all you need.

One other cause of the transmission Limp Home Mode (LHM) when the transmission locks in one gear and the warning lamp illuminates on the dash is oil contamination of the Throttle Position Sensor (TPS), which is mounted on the throttle body.

Please check the fluid and report back to us and we'll go from there.

Cheers,

Don

 

Thanks everyone for replies! I will definitely check fluid level.

I will add that tomorrow, good idea. : -)
And I am driving in normal mode. Although in sport mode it is more responsive and downshift more to my liking, normal upshift earlier and I am more of a relaxed driver for most of the time.



As for holding gears. I don't think that convertor lockup is involved. Once I was locked in first gear for 10 seconds and there is no lockup. Or at least shouldn't be. Several times in second gear.
But as mentioned, I will check fluid lever and then we will see. : -) If I understand the procedure correctly, there shouldn't be any dripping from the hole when transmission oil is below 35 celsius, should it?
Btw. tried to floor it today, no problem at all. No problem since last week.

 

Oil should be running out, slow trickle. If not you don't know how much is in there. I believe the torque converter only locks in 5th.

 

So, update.
Finally I found time to check oil level. Well, to keep it short, after I was done with check, around half a gallon of oil was left on the ground and now I am waiting for oil to top it...but there was enough oil. It was nearly dripping at around 37 Celsius. Also the oil was looking very good, clear and was not smelling like burned oil. Also since the incident few weeks ago, no other fault happened and the car goes fine. Although I have to say, I am driving very gently, but I did pressed it hard down few times, just to see what happens.
So next course of action is to see, if the error occurs again and then I will think what to do next. Anyone have any better idea?
And another question. I mentioned it earlier, does any of you experience the same behaviour of it's transmission as do I?
"When I go uphill and have the pedal pressed around halfway down (not sure how much, just guessing) for at least 10 seconds (again, may be minus few seconds). Afterwards I press it even more, but still not into kickdown and hold it there for a few seconds (2-3 is enough). Car downshifts by one gear, but when I release the pedal, even fully, the car stays at the same gear for nearly 10 seconds before upshifting again."
A little off topic, but I went to clear throttle body and found out, that half of the shutter was painted with something grey (the half, that when throttle is pressed turns into the engine). Like for a compression test or something like that. Anyone know what was it good for? I cleaned it, well most of it and no effect so far. Which reminds me, the car do shake, like missing, for a few seconds after starts when cold. Any well known reason for that? (I will check sparkplugs.)
Btw. thank you all for your help. Much appreciated. : -)

 

Hi myskoc - I can't really add to the suggestions (all very good btw) on the transmission, although I will ask a fundamental question (I like asking as it saves time) how old is your battery? If it's the original, it might be a good time to buy a new one. Basically these cars require a minimum 12.5V to perform, anything less will cause random and sometimes oddball faults.

A lumpy idle can be 1001 things, but if you're starting the car up from short trips to the shop round the corner for example? this is another issue.

I won't go into detail but your engine (98) has a common issue with fuel washing oil from the cylinder walls, which leads to loss of compression.

The advice here is to only use the car on trips that allow it to fully warm up, or let it come up to temp in the driveway before setting off. Jaguar has updated files for cold starts but it's a trip to the Dealer to reprogram the car.

Hope this helps

 

Not sure if this helps explain what is happening but the transmission (not in sport mode) has a "program" that determines the load and possibly the inclination and will hold the gear that it down shifts to so the transmission doesn't hunt. It will also hold a gear going around a turn and not shift up so that the whole understeer vs oversteer thing doesn't change. I live it the foothills of the Catskill Mtns in NY and at times this feature can be annoying as sounds like your screaming. It will wait till it thinks it can hold the next gear up and give you the performance it thinks you require. Hope this helps. It is in the manual section 2 of the Drivers Handbook.
Why the fault? Not sure I can help you there. The Battery being low is definitely a known issue.
Once again hope this helps.

 

Walter2: Thanks, that exactly what I was hopping for. Some experience. I of course looked into manual and found out about those "modes" that the transmission have, but they are not explained in details. Meaning I was not sure, that this behaviour fits pattern of one of those modes. That is why I needed someone else's experience.
About battery, that is very unlikely, since this happened after maybe half an hour of driving. And never since, even when the car was sitting for nearly two weeks. But of course, I can't rule that one either. Thanks a lot for your reply!

Btw. anyone does experience the same behaviour? Just to be sure. : -)

 

Sorry, missed your response at first. : -)...Don't know about battery, but apart from the limp mode once, no random fault or anything. But of course, that doesn't necessarily mean, that it is all right. I will take a look, if it is original or not. : -)
Well, relatively short. I of course read about the washing of interior by petrol, but that shouldn't be the case, since the car (at least on the gauge) is at operating temperature before I turn it off. And I mostly drive for around 15 minutes, before shutting it down. But of course, I don't know for sure, if that is fine.

 

So, hopefully last status update. Battery was little below 12.5V (12.4V) when plugged into the car electric system. But that is taken care of now. But since that one fault mode many weeks ago, everything works fine. I also got my hands on another manual considering transmission and finally they have there explained behaviour under certain modes in more details, so it is normal that it holds gear under certain conditions. So only one problem, that I am worried about, remains. But I am going to start a new thread, since it is not relevant to transmission.
And thank you all for your help! Much appreciated. : -)

 

After I posted my reply I was having all sorts of problems with my transmission and faults and limp home mode, worse asking for power up hill. Changed the battery when the cooling fans would kill the battery after running for 5 min in hot weather. Changed the battery and 99% of the trans problems went away. Now rough shifts up and down for second otherwise fine.
Hope this helps someone else. Wish I had listened to the guys here before possibly hurting 2nd but will drive it till wheels fall off.
Walter2

 

Well, as a follow up. I so wish I had changed that battery earlier. The problems it created for 2nd have gotten worse. Pretty much have to coast through 2nd and wait for 3rd. Car has 150,000 miles now. That voltage is so important. If you think battery is going test it or replace it!