No, actually, it wouldn't be evident. If the shop put a crease in the shaft, which is what every mechanic I've spoken to thinks happened, and then the driveshaft rips at that point, in the process of ripping at the seam the evidence of a crease will be destroyed.

I think the better evidence will be the condition of the shaft and driivetrain everywhere else. If you look at the photos you'll see the car is exceptionally clean underneath. (It is after all a Southern California car that almost never sees rain and has never seen snow that just turned 70k the week this happened.)

Plus there is human common sense here. The car is driven 70k miles. As Jaguar puts it, if there was a manufacturing defect in the shaft that would result in that sort of failure it would have happened sooner. Moreover, I have driven the car quickly at times. However, after getting the car back I was mostly driving in traffic and there was no driving it quickly and thus no usage of its 400 pounds of torque.....and this happened when rolling away with part throttle on a green light.

It did not happen over 11 years....only happened 30 miles after picking it up from the shop....where they replaced the rear plug on the transmission....inches from where the shaft failed.

Another thing the Jaguar service manager noted was, if there was an issue with the shaft, such that it would fail, then why didn't the shop notice this?

So far every Jaguar parts specialist, tech and service manager (now 3 different ones) all say it was not a manufacturing defect and that the shop likely put a crease in the shaft...probably with a pry bar.

 

This is exactly what the Jaguar specialists (service managers, mechanics and recyclers) I've spoken to have all suggested as well.

 

Thank you for your offer. I will forward you pics of the components once I get them back from the shop. As for the information I got from Jaguar, I've now spoken to several service managers....guys who have been doing Jaguar service for decades. So there opinion is from the front line. If there was a known manufacturing defect with Jaguar XJs they would have known it. There are at least two ways to determine something in this instance, one is through analyzing the metal....the other is through the chain of events. As you say, just like with an aircraft.

At the end of the day I think this is pretty darn obvious. If I'd taken the car from the shop and gone to the track or drag racing I could understand a driveshaft failure. But driving a pristine XJ 30 miles and having the shaft rip in two while puttering away from a traffic light in LA traffic leads me to the rather obvious conclusion, a conclusion supported by Jaguar experts. Moreover, the fact that no one else on the forum has said they had a driveshaft failure on their 2004-2008 XJ is further evidence that these shafts are sufficient for their designed purpose.

 

Similar to cjd, relevant and direct experience from the aircraft accident investigation world demonstrates that there would be plenty of residual clues left behind. Statements laying blame one way or the other based on the current photos is shooting from the hip at best.

Up to you if you want to take advantage of the offer or not.

 

Wow. It would have to have been a significant dent, almost where the metal had to have cracked for this to occur. Even a dent, IMO, would have taken a long time to weaken and shear. My guess is they jacked the tranny/prop while the jack was under the prop itself. It may have been fine for a while, then the weight eventually creased/cracked the prop metal suddenly.


Or they had a jack that slipped and caught under the prop, creasing/cracking the shaft.

 

Now, for the record, you cannot believe anything that anyone paid by Jaguar says. I know for a fact that they are trained to deny anything that goes wrong with their cars. I've had them deny problems with parts that were later recalled.

Small damage or flaws can take millions of cycles to fail. Large damage can fail in one cycle. As long as you have the complete shaft, any creasing will be obvious.

 

Well, "trained to deny" might be somewhat strong. Anecdotally,
what we have is that prop shaft failures have not been reported
on JF at all.

But, it is plain that offering an opinion based on verbal description
is not very reliable or even useful.

Photos are more reliable. Direct physical examination by a trained and
experienced investigator even more so.

 

I second your vote, something was either lifted up or dropped onto (meaning the weight of the car coming down a lift etc.).

I do agree however, that the subsequent inbalance of the shaft would be very noticable, unless speeds in those 30 miles were very slow.

Regardless, if the shop didn't do this (which is highly doubtful that they did NOT), they should have been astute enough to notice the shaft either having a massive dent or the like, being that they spent two flippen hours in that general area.

There should be evidence of the impact though, as if it's a clean break, with no heat distortion in color, the only other option is fatigue / sheer, but unless you were doing burnouts, that would be one helluva chance happening / time to buy a lottery ticket!

Sorry for the ordeal!

Jeff

 

Mikey, how would the damage be "quite evident?" I've since spoken with Service managers for three of the top Jaguar dealers in the U.S., guys with 26 years experience or more, and all three say the same thing. Shop error.

Now, if the shaft failed due to a crease, well then, the crease area would be destroyed by the ripped apart shaft. That's pretty obvious. If you grenade something its rather difficult to tell what it looked like before its torn apart. That is evident.

 

Thanks Jeff. Unfortunately with LA traffic during the day speeds on LA roads often times don't get much above 30 mph. It's mostly stop and go during the day. Nope, wasn't doing burnouts. Those 20" tires would be pricey to replace!

 

Other than simply repeating what has already said by several posters, there's not much more to add at this point. If you'd rather put faith in the opinions of people that have no relevant experience in the field, that's fine.

 

To use the beer can example...

If you crease a beer can, and then later rip it apart, there is always a sign of the initial crease. Metal work hardens when it is creased, and that crease will never be straightened back out without a sign that it was there.

 

If you put several experienced automotive service managers in a hangar
with crash debris from Malaysia Flight 360 ... what could they tell you
conclusively about the cause of the crash?

a) nothing
b) less than nothing
c) none of the above

 

Ah, but I have an aviation degree and many class hours, many moons ago (all forgotten) pretaining to accident investigation, AND I can tell you, without a doubt...

The driveshaft broke and should be replaced.. HA!

That's a part of my life I'm glad is over, terra firma please.

Jeff

 

Sorry, your analogy makes no sense. The Service Managers and their senior techs they conferred with have Jaguar experience, not aircraft experience.

 

Just to add to last posting, I spoke with ZF directly and on of their in house tech guys. His conclusion was the same as the three Jaguar experts.

 

That's all good but what's the point unless you plan to sue the shop that did the work or they decide to admit fault.

 

It's all going to come down as a he said/she said case. With all the BS dealing with courts, lawyers, etc., you might as well just find a new shaft on Ebay. It sucks, but unless they admit to it, it will cost you more to fight it than to just replace it.

 

Did you find any other "new" scratches or marks near where the shaft broke that could have been made by the shop?
Discount any scratches/marks done by the shaft breaking.

 

Actually small claims court is up to $6k+ in most states. You still have to show proof, though. So, the cost of the shaft AND and engineer assessment would still keep you in the small claims realm.

But, we are still getting ahead...PIC's!

I figure you know, but I still feel like I better point out...when the parts come off, do not allow the mechanic to start poking at the broken edges or try to fit them together. Messing with the broken edges WILL destroy any evidence one way or another. Fatigue beach marks can be almost microscopic, so just rubbing them together is enough to destroy them.