My automatic box failed at ~85k miles and 12 years old.

My local auto repair guy rebuilt it for me using the latest ZF parts. As normal the forward clutch pack housing had a fatigue failure around the holding ring groove (like a big circlip groove), I took some photos while it was being rebuilt, I'll try and post them as it shows the weak point.
He showed me the latest ZF part and when (in the UK) you order the original ZF part number you receive a modified part which is thicker around the groove! He had done guite a few of these on BMWs and Jags, he described the symptoms and the problem as soon as I said it was an XK8 which went into limp home Gearbox mode... and he was correct.

 

Alastair, definitely a reat idea to post your pics when you get to them. If you have a ZF part number(s), even better.

 

My 06 xk8 is at the dealer right now for the 30,000 mile check up, still under warranty. On the list of things to be done programming up dates on the trans. Anyone else had this done. No problems with trans so makes me wonder what it will do.

 

my 98 xk8 is still going strong and no fluid change. have a great mechanic, he just replaced just the front ball joints without replacing the whole part.

 

As promised, a photo of the fatigue failed forward clutch pack (1st and 2nd gear), you can see that the retaining ring groove has broken away at the back of the housing and is bending outward on the right. I only had the 'bang' on pulling away symptom and limp home mode during one week of low mileage driving before I had the box removed and stripped.... good job!

What happens:
The pack of clutches is held within the housing, when Drive is selected Oil is let into the pack loading up the retaining ring, repeatedly this fatigues the groove and it brakes away, the remaining groove fails quicker as the stress is that much greater on what remains. When the pack begins to seperate the clutches slip more than the ECU expects and it depressurises the pack and opts for 3&4 instead (that is the cause of the 'bang'). As the ECU has detected clutch pack slippage it goes into limp home mode and annunciates a Dash message.

 

Had the same situation and had to replace the A&B drum and the torque converter for fears that the shavings went into the converter and could cause additional problems.

I began working on a post for my page and this is it http://www.gusglikas.com/AutoRepairTransZF5HP24.htm

 

nice follow up post! Looks similar to what Gus was facing on his a-drum, IIRC.

 

65k miles flush and fill with mobile one. Currently working on removal. I had a big BANG 2k miles later.

 

At 81,000 my 98 XK8 broke it's flex coupling. New rebuild kit $1808, flex coupling $544, 4 valve body pistons $249, new torque converter $500. No service had ever been done on the tranny. The fluid at teardown was slightly brown instead of honey colored but a flush and refill would not have prevented the coupler from breaking. I guess it was it's time to die.

 

Mine failed at 94k. The rebuilder said they all went on all xk8's and xj8's at about the same mileage(Same tranny). The same thing seems to happen to all of them. Something about some thrust bearing inside(I started zoning out when he explained, I just wanted it fixed fast). So, my new tranny will last about the same.

The newer 6 speeds have proven much more reliable

 

Of yeah. It was $2,200 for the full rebuild with warranty, not too bad I think

 

70k miles on my '01. Never been serviced, to my knowledge.

So: is there a consensus on this ... should it be serviced or no, given that I plan to keep the car through about 90k miles?

TIA for any advise,

 

ZF's current recommendation is for ATF fluid change at 100k miles under 'normal' driving conditions. They also recommend change at 60k miles for 'severe' driving conditions. The problem is that the definition of 'severe' contains many of what many in the US would consider 'normal' conditions.

MY consensus is to change it at 60k miles. One more thousand to go.

 

Agree - change it.

 

I see that this is an old post--- but being a new member I think the info is valuable.
I am the 3rd owner of a 2000 XK8 I bought in January 2010 with 68,000 miles. I have no records of a fluid change. I put 2,000 miles on this summer with no problems.
However, the English Jaguar guru Nigel Thorley in his book “Jaguar XK8” strongly recommends a fluid change at 50,000 miles to extend the life of the transmission. He states that the ZF forward clutch pack has a retaining clip that wears through the pressed steel housing and falls away. He further states that in the XKR its a problem with the output shaft assemblies and planatary sets breaking up. Hence, beware of slippage between gears ,
Thus I will be changing mine come spring.
This is an important topic. Thanks for bringing it up!
Tom

 

I changer mine at 113,000 and I'm glad I did. Not that the fluid was black, it wasn't. Its just that now I know what I've got. I did'nt change the torque converter. Maybe I would have if the fluid looked bad.