In terms of my comments, I'm suggesting that if you feel the shudder currently, it's like a cavity in a tooth - not going to get better or go away on its own. But if you DON'T feel it now, especially given that the car has some miles on it, probably your diff is fine and I wouldn't give it a second thought. Like I said, I felt it subtly for a whle. In comparison, I don't feel it at all now with the replacement diff.

Also: the warning light came on, intermittently, during a long trip. I'd say I put about 1,000 mostly-highway miles on the car AFTER I first saw it. I never noticed any difference in the way the car drove. As I wrote, one tech pointed out that probably most of the fancy things about the e-diff had been disabled (couldn't put it into Dynamic Mode), and at that point I was simply driving a car with an old-school differential. Had to get it fixed at some point, but wasn't in any peril. Never thought there was any danger of anything worse happening.
I did talk to an experienced indie shop who urged me to go to a dealer. He was the first person who clued me in to the fact that for Jaguar it's an all-or-nothing thing with these diffs. They don't replace internal parts piecemeal. My hunch is that Jaguar knows of this issue this and just swaps them out when certain codes show up.
2010 was the first year of the e-differential. I think it got worked out after that, and like I said my hunch is that the diffs on most cars, even 2010's, are fine.
Hope that helps, and didn't add to any confusion!

 

Just messaged you about this-- long story short, the original is long gone. Didn't really get into whether they'd have given it to me if I'd asked at the time.

I'm doubtful - wouldn't a differential be like a battery or a water pump or the like? There's a "core charge" if you don't bring back (or have them keep) the original? (I'm having flashbacks of my long-ago mechanic days, standing in line with that beat-up cardboard box with a nasty old heater core or something, waiting to get my core charge back...)

 

I had a similar question PK. Here in Minnesota, if a shop replaces a part, they have to return the original to you - you being the payor, so in this case your warranty company, but the added question of core charge could also come into play.
Again, in my State, I would pay additional $ if I don't want to return the core. I still have the right to inspect the part before it's returned though.

I imagine this law plays out differently from State to State.

 

Yeah I think your right. Though I did pay for the warranty, I didn't pay for the part. In fact, the warranty company supplied the part to the Jag dealer. But with something like this... who knows?

 

Cheers mate!
If there ever was a chance, it was here with you paying full price and NY folks are cool and have no space. It was worth a shot.

p.s the reason they replaced instead of repair is that its really skilled specialized work, on any car, not something an average wrench can do.

 

PK - I would really like the name and contact info for the warranty issuer. When you have a chance please. Thanks.

 

Sorry man - thought I'd gotten back on this!

If you scroll up, the FIDELITY phone # is on the dealer's repair invoice that I copied in my original post.
If you don't see it, let me know.

 

the e-diff shudder is become a common issue for 2010 and 2011 R cars (my XFR had the shudder). Definitely something people should look out for

i flushed out the diff fluid and noticed the shudder is completely gone. maybe i caught it before it was too late.

 

What brand and type of fluid?

Did you have to add in limited slip supplement?

I have had amazing performance from Amsoil and Lubegard in other cars.

 

How many quarts do our diffs take? I think I want to get this done.

Did you use a specific brand? Or went OEM?

 

If my car was out of warranty I'd to that IMMEDIATELY. Take a look at my invoice that I attached, especially this:

"35188 rear differential metal filings."

I read that and thought "what the HELL??" I actually wondered if someone forgot to add the fluid originally, or if it had all leaked out, or if it was somehow defective.

And if it's mostly on "R" cars... do we have a different setup back there? (And why?) Or is it an issue of increased torque/stress?

 

I also wonder if someone could tell me what a "clutch actuator" is on a differential..?(which was apparently defective on my car, according to the invoice)

 

A good shop looking out for you will usually have a bottle of filings laying around. (its an indisputable sign of faulty assembly)
Its normal to see filings in differential fluid- thats why typically they have a magnet in there to catch it. If there was abnormal wear, you would hear it long before any light or code was thrown. Its almost unbearable sound, particularly on the highway.

 

As I understand it the E-diff. or electronic diff. is activated electrically when slippage is detected on the wheels. A normal positraction works mechanically with clutches in the diff. This is done with an actuator in these cars.

 

In order to understand if this is a common problem we would have to know how many units failed and how many were built. My dealer has not heard of this issue and has no factory data that supports it.

 

The XKRs from 2010+ have E-differentials. The XKs do not.

 

Back to the "shudder," does the wheel have to be turned all the way left? And does it start immediately or part way into a turn?

 

to be honest im not too sure of the details. I gave it to the garage and they told me they'd contact jaguar for the details. whether they used OEM brand or just a similar fluid weight.


right, but at the same time there's SOOO much jaguar wont admint to...but if you search the forums, you'll see a lot reports for the same

 

Doing this from memory, but... no, I don't think the wheel has to be fully left. And you start noticing it pretty quick once you start that left turn.

Remember, the "left-across-traffic-from-a-stop" is itself a pretty quick maneuver, so you're out of it pretty quick. (I never felt the shudder/vibration in straight-line driving.) It's simple: find some quiet stop-sign intersection. Come to a stop. Make a left a little aggressively, and quickly (no need to go crazy here). If you have the issue, you'll feel it in the seat of your pants, and it will definitely feel like it's coming from behind you and not in front of you. It's not a "steering wheel shudder from the front end" feeling at all. And I don't think it ever began while moving, I think it was always from a stop. And it slowly became more noticeable and in the end was happening on right turns as well. I live in a part of LA where I'm making a fair number of those left turns from a stop.


Hope that helps.

 

right, but at the same time there's SOOO much jaguar wont admint to...but if you search the forums, you'll see a lot reports for the same[/QUOTE]


Yeah I think so too, simply because I got no grief/follow-up/haggling from the warranty company. My hunch is the codes read a certain way and it was like "oh yeah, that" because it's not that rare in these cars. Just a hunch.