XK8 transmission problem...

[Alien911]

Hi, I was impressed by the answers from some of the members on Jaguar XK8 transmission functions so I am giving it a shot to resolve my problem:

The car: 1998 Jaguar XK8 130,000 miles.
The tranny: ZF5HP24 (as far as I know)

When driving at speeds between 45 and 60mph the transmission is making a loud grinding noise. It only happends when I lightly accelerate at those speeds. I keep the "Sport" mode on because otherwise the same problem occurs at lower speeds. However, if I give it more gas the noise goes away. It also feels like a slight power loss when the noise is present and the RPM drops a bit from 2000 to about 1950 rpm.

Drove it with a transmission tech (non-Jaguar) and he said that it makes noise when transmission goes into a "lock-up" mode but he can't be certain unless we remove the box and look inside...

So... before I spend around $3500 or let go of my favorite car I would like to make sure I tried everything else.

Questions:
1. Will replacement of torque converter help?
2. Is there a way to diagnose the box without removing? Jaguar dealer?
3. Does the recall on transmission still apply to my car? Dealer has denied that there is such a thing as a recall on tranny , however i got the recall number from AllData and confirmed on the internet?

Any information is highly appreciated as it is a very important decision for me: I favor this car over my 79 Corvette and 66 Mustang.

thanks in advance

[Trooper2]

Alien911 said:

When driving at speeds between 45 and 60mph the transmission is making a loud grinding noise. It only happends when I lightly accelerate at those speeds. I keep the "Sport" mode on because otherwise the same problem occurs at lower speeds. However, if I give it more gas the noise goes away. It also feels like a slight power loss when the noise is present and the RPM drops a bit from 2000 to about 1950 rpm.

Questions:
1. Will replacement of torque converter help?
2. Is there a way to diagnose the box without removing? Jaguar dealer?
3. Does the recall on transmission still apply to my car? Dealer has denied that there is such a thing as a recall on tranny , however i got the recall number from AllData and confirmed on the internet?

1. Your symptoms certainly sound like a TCC (torque converter clutch) lining failure.

2. If the Transmission Control Module detects the TCC is slipping it should, I think, disable the TCC in the off position and also set a diagnostic trouble code, but that may be only on the newer transmissions, so the answer is maybe. I would think that if the TCC lining was disintegrating that the trans fluid would be dark brown and smell burnt which could give a clue.

3. There was a recall on the ZF5hp24 in the 1998 XK8 coupe for hairline cracks in gear teeth, it didn't effect all 1998 XK8's just a certain VIN range so your vehicle would have to be in that VIN range to qualify. A dealership would be able to tell you for sure if your XK8 is eligible.


.....and depending on what Gavin has to say about your problem this may just be a "BUMP"...

[Alien911]

Thanks, and I did forget to mention: at any time there was no trouble codes at all. I also had checked the fluid level while the car was on the lift and it looked perfect and clear fluid. Did not have to add anymore (which I hoped was the case)

[GavinPearson]

The 5HP24 has a slip control converter and is in partial lock up or lock up 95% of the time.

Having read the post several times I think I need more information. Just answer as best you can.

1) How was the car checked for codes? Using dealer equipment?
2) How was the oil level checked? With the engine running?
3) When you drive the car, can you use the throttle to provoke the condition and at what speeds does the problem come, and go?
4) Does the problem come when the throttle is pressed, or you lift off?
5) Has a stall test been run?
6) Does the car feel sluggish or is performance normal with just the noise worrying you?

[Alien911]

1. Did not use dealer equipment, just the message center (yellow/red lights) none present.
2. Oil checked with the engine running and A/C on, as per instructions from AllData, shifting through the gears with 3 sec in each position
3. The throttle is what provokes the noise. It happends when it is in the last (5th I assume) gear and I slightly accelerate to speed up a bit, usually at 2000 rpm and speed between 45-65 mph. It only happends on acceleration and accelerating harder , say to 2200 rpm makes it go away. Basically, imagine I get to 50mph, and the "rolls" with traffic, then, in order to keep up I have to slightly accelerate to maintain the same speed and that is when the noise occurs. The car feels a bit "slipping" and loud grinding with it.
5. Stall test has not been done. I don't even know where should I do that. I am not much of "dealer" person - they also sell Ferrari and Maserratti so they froun on my Jag
6. Performance is not normal, feels sluggish, but revving up and going faster makes it go away. That makes me drive it at 70-75mph at least and people think that I am just showing off (like I got nothing better to do...)

PS. Just wanted everyone know that I appreciate your time and help as I got more information in one day reading this message board than talking to dealer and transmission shops for 4 month...

[GavinPearson]

Alien911 said:

1. Did not use dealer equipment, just the message center (yellow/red lights) none present.
2. Oil checked with the engine running and A/C on, as per instructions from AllData, shifting through the gears with 3 sec in each position
3. The throttle is what provokes the noise. It happends when it is in the last (5th I assume) gear and I slightly accelerate to speed up a bit, usually at 2000 rpm and speed between 45-65 mph. It only happends on acceleration and accelerating harder , say to 2200 rpm makes it go away. Basically, imagine I get to 50mph, and the "rolls" with traffic, then, in order to keep up I have to slightly accelerate to maintain the same speed and that is when the noise occurs. The car feels a bit "slipping" and loud grinding with it.
5. Stall test has not been done. I don't even know where should I do that. I am not much of "dealer" person - they also sell Ferrari and Maserratti so they froun on my Jag
6. Performance is not normal, feels sluggish, but revving up and going faster makes it go away. That makes me drive it at 70-75mph at least and people think that I am just showing off (like I got nothing better to do...)

PS. Just wanted everyone know that I appreciate your time and help as I got more information in one day reading this message board than talking to dealer and transmission shops for 4 month...

You need to be aware that there are several types of fault codes that I'll split into two groups - those that trip the fault lights and those that don't.
It really sounds like the converter has a stator problem and that wouldn't come up as a fault code but would explain the generally sluggish performance at the low end. A stall test wuld help diagnose that.
The issue is really then what do you do?
Based on what I read, I would think that a new converter would be the most appropriate repair, you also need to drain all the fluid, remove the pan and change the filter. You also need to flush the cooler lines when the transmission is removed.
I hope this helps.

[Alien911]

Thank you very much, man. Just one last question, that I can't answer myself: where can I buy a new converter? And I am not intending to replace it myself, just want to get a price idea. Google search did not help me a bit

[GavinPearson]

You can get them from your friendly Jag dealer. Or phone ZF in Nottingham and ask them.

[Alien911]

Just looked in the MitchelOnDemand today - $1250 for a torque converter... I also checked ODBII codes - nothing in the memory, just one trouble-free Jaguar, rrrrright... Thanks anyway, man, I really appreciate your time.

[Trooper2]

Hey Alien911, Direct Transmissions Parts (NY) has re-manned converters on Ebay for $350.00 with 100% feedback, you may want to look into:

http://cgi.ebay.com/ebaymotors/ZF5HP1


or you may want to give a call to Pheonix Remanufactured Transmissions (AZ) and see what they get for one:

www.phoenixhardparts.com/




Gavin's so handy to have around....

Good luck!

[GavinPearson]

Probably more for Trooper2's benefit than anybody in the UK I find that these people are very competitive on ZF parts, and are authorised by ZF USA to supply parts and reman transmissions:

www.autosportsunlimited.com/index.html


Looking at what is available in the UK the following links will be of use, but I have no experience of dealing with said company.
www.jpat.co.uk/jpat_pdfs/ZF%20Acrobat%20files/ZF%20%205HP24.pdf

www.jpat.co.uk/index.htm

[Trooper2]

I was going to suggest that Alien911 give JPAT a call until I saw he's in Texas....


I'm Not sure what Prices are like at Phoenix Transmission, but they have a good reputation. Thanks as always for the info.

[GavinPearson]

I reckon Auto Sports Unlimited will offer much better quality though.

I have visited a lot of big name rebuilders as part of my job and most are junk runners.

Not what you want for your pride and joy.