X350 XJ Sovereign Diesel 2006

I'm getting a heavy gear change and surging on what I presume to be the 2nd and 3rd gears.

Originally it was just the 2nd gear... occurring roughly between 20mph and 30mph.

No matter how gently I drive the car I feel the change and then the engine surge.

Car has only 60,000 miles and a new engine since 35,000.

Does this sound like the death knell for the gear box?

 

If were me:
1.I would get the gear fluid changed (no filter) using Mobile 1, because it's cheaper and no use putting in super expensive filter/fluid if it doesn't work.

2. Have the xmission re flashed - a software procedure most likely, but not necessarily, performed at a dealership.





If the above does not work get ready to have your bank acct Hoovered up because you got a xmission on the way out. I hope I'm wrong about this but that my take on your symptoms.

 

Hi Acebars,

The gasoline/petrol X350s use a ZF gearbox (6HP26). The part number for the diesel engines is different, so search this forum for more information on the transmission in your diesel.

Some owners have reported transmission problems that were corrected with a new battery or cleaning the battery power connections in the car to improve battery charging.

Also, search the forum for posts about the re-flash of the TCU (Transmission Control Unit) that tarhealcracker mentioned. That may very well be your first order of business.

Also search for posts about the transmission fluid and filter change. Opinions vary about which fluid(s) is/are suitable for the X350 gearboxes, and the correct fluid will depend on which gearbox you have. Don't assume you can put just any modern fluid in your gearbox. Today's transmissions are designed with very specific fluid properties in mind (viscosity index, etc.), so it is very important that you never put an incorrect fluid in your transmission. I believe that many of the post-fluid-change transmission problems reported are from owners who ignored the manufacturer's fluid specifications, assuming any good brand of synthetic ATF would work. There are reasons ZF does not list its Lifeguard 5, 6 or 8 fluids as backward compatible with each other or earlier fluids:

http://www.zf.com/na/content/media/u...omendation.pdf


Please keep us informed.

Cheers,

Don

 

Thanks everyone I'm taking the car in on Monday to an independent Jag specialist to get it checked. The battery is new and I had the transmission reflashed last year which dealt with lurching but the gear problem was there although not as acute, it was only between 2nd and 3rd then.

It's the 2nd time I've head the mention of transmission fluid and filter change actually from the garage itself last year when the problem first became apparent. They'll be doing the work so if I do change it, it'll be done properly.

After long motorway riding you are almost guaranteed a gearbox fault message and gear in limp. 65,000 miles so far on the car. Engine has only 30,000. I believe the diesel gearbox is a merc box.

 

Just to let everyone know I ended up needing a new gearbox, turns out the valve block was buggered, very rare apparently.

Another ouch with my the jag, it is a headache but I still love it.

So far new engine, new gearbox, new suspension compressor, new roof console, several other minor issues and only 30,000 miles since the new engine, 65,000 total, owned it from brand new.