Driving along the motorway at a steady 80mph, suddenly yellow light comes on with gearbox fault on the display, a few expletives later I pull off motorway driving steadily think what is wrong, but everything seems ok, changing gear ok, drive a further 20 or so miles to home no problem. Park up on the drive, switch off, fetch reader out of garage plug in start engine gearbox fault from display gone but P0741 on the reader. https://usait.x431.com/Home/Report/r...type/D/l/en-us

 

The obvious question is what is the mileage of the car and when was the transmission fluid and gearbox filter last changed?

If it has not been changed, and most have not, and the car has done more than 75k miles then a fluid and filter change is due as soon as possible.

Richard

 

Info we go a few decades ago when I worked at the dealer.

 

Thanks guys, motorcarman that is basically what the transmission specialist said might be the case quoted me a price of £1300, is there anything else you would recommend while they have the box out as a preemptive measure

 

I would replace pan/filter, fluid and TCM sleeve.

You won't lose too much fluid if you fill the replacement Torque Converter with fluid but I would change the fluid anyway?

 

Just heard back from the transmission specialists, apparently due to the amount of mileage 120000 and the way it drives, which I don’t understand because it’s the best performing auto gearbox and seems faultless to me that I’ve driven, instead of just changing the torque converter they will only do a complete overhaul costing £3500, does this sound odd to anyone else or does it sound reasonable and of the cost does that sound about right?

 

I had the fault come up a few times but a fluid change fixed it for me. Best to start there before doing full transmission rebuilds as they are pretty expensive. £3500 for a rebuild is about right though but like I say £400-500 for a transmission fluid and filter change might fix the problem. There is also a conenctor block and some rubber tubes inside that compress and degrade allowing fluid to bypass which reduces oil pressure there so that could also be the issue. Not difficult or expensive to sort out.

 

How much experience does the trans shop have with these trans? The rebuild price sounds in the ballpark, but needing a complete rebuild at 120K seems far-fetched unless the trans was abused.

Were it mine, I'd change fluid, filters, and sleeves, and drive it. If the error comes back, OK. But these trans are noted for having the sleeves harden and lose their ability to seal correctly, causing odd behavior.

Again, were it mine, and it did need a rebuild, and I couldn't DIY, I'd strongly consider having the shop install a low-mileage used trans. Rebuild the converter while the trans is out, do the sleeves on the replacement unit, and send it. Lots cheaper than a full-on rebuild. I looked into rebuilding mine before I figured out what was wrong, and the parts for these trans are pricey.

 

At 120k miles the gearbox is well past the time at which the fluid and filter should have been changed. As I suggested above, have this done, or do it yourself, before drawing any firm conclusions about the state of the gearbox.

Richard

 

^^ I concur. My wife's 2006 XK8 has 126,500 well-cared-for miles. We have done three ATF drain-and-fills (using Mercon SP) during our ownership (car acquired in early February 2012 at 36,000 miles). Her ZF 6HP26 continues to perform exactly as designed. Refreshing the ATF in these cars at reasonable intervals is crucial to keeping them happy and healthy....

 

Thanks for all your replies, I will get the box serviced when I get back from my holiday, it also needs an mot so I’ll get it all done at the same, although my independent is always busy , which is a good thing as far as I’m concerned, it means he’s good.