Hello All, I have a harmonic hum that started as soon as the temp has dropped recently, a -3 cold start kicked it off and it's been there ever since. I have an 05 3.0 Sport Premium Auto Est, 36k with full Jag history. It had a new transfer box 6000m ago just as the factory warranty expired....Jag have listened to it and want to put yet another new transfer box in (£1100+ with Jag contribution parts only 25%) but, they have also confirmed the T box is leak free and it's oil not contaminated by particles etc. They are convinced the noise is from that area and not the propshaft - which they have dismissed as the noise is from the T box area....can it really be T box number 3 for this car? Anything I can try to eleminate/confirm the prop? Thanks!

 

PG1, if jaguar is willing to work with you on this, have them grease the propeller shaft anyways. It is a 5 minute job and for some, it makes the noise go away. Normally, the propeller shaft will only "hum" between like 30-50 mph (50-80 KM/HR). IT is possible that the transfer case is going again. But, I would find it hard to believe that unless you are really hard on the car and like to accelerate really hard a lot.

Another thing that I would ask you to check is does the hum change when you turn left and right? if so, then you are possibly hearing a wheel bearing, not a transfer case. For reference, normally they will make the same amount of noise when you turn one way and will make no noise when you turn the other way. The direction that you turn that makes the noise go away is normally the bad bearing in question in this case. Along those same lines, you should have Jag look at the boots on the half shafts and make sure that they are not ripped, causing the CV joints to run dry. That can cause them to make all sorts of noises. Granted, I would expect the mechanic to see that as it tends to make a pretty decent mess on the underside of the car (which is sounds like they looked for).

Wish you luck. You can do the propeller bearing in your driveway. All it takes is a grease gun (loaded with Termalene grease), a needle attachment, a jack, and a pair of jack stands. You lift up one side of the car, support it with the jack stands, crawl under and look for a loop of metal that is wrapped around the rear driveshaft. You will see a small gap in the bearing, slide the needle attachment in and squirt in grease til it comes out. Move around part way on the bearing, put the needle back in and squirt in more. Keep going around till you have made it all the way around. Drive the car and see what the noise is now.

 

Many thanks for the detailed reply, will give it a go and let you know. Strangely, my father in laws X has just started doing the exact same noise this week...whatever it turns out to be, I am sure this cold weather has triggered it.....watch this space!

 

Did the regrease, still the same this morning (9 degrees here) but it goes completely after 3 or 4 miles. Translator, thanks for your response, sorry I posted in the wrong section. What would you guys suggest - I really don't want to throw money at the main dealer as they just want to fit brand new parts for big money, so may try a Jag specialist who can fit reconditioned parts?

 

Hello again, well I finished the sandwich and found a bit more info; (I am not well versed with your X type).

However apparently this is a common problem and is discussed on all sorts of boards.

From what I read (and you can confirm this yourself) it looks like it would be the prop shaft bearing and YES it seems to be temperature related.

Apparently below 50F ambient it will hum until it gets warmed up.

How wierd is that?

Hopefully one of our Tech's can chime in.

 

PG1, here is a silly question, did you get new tires since last winter? it is possible that your new tires develop slight flat spots and after a few miles of driving, the flatspots go away, getting rid of your hum.

 

I did put new tyres on last summer but, it makes this noise when up in the air on a 2 post ramp with no ground contact....I guess I just either wait until the weather warms up and hope it goes away, thing is I want to sell it soon without spending loads of £ or, having to try and explain it away to a prospective buyer. It does it at precisely 24-26 mph, mostly when slowin down through these speeds but never after a few miles....maybe I just forget it.

 

Well it's finally above 10F / 50C here in the UK but my hum noise although much better than in the really cold weather is still persisting - until warmed up anyway....I want to sell the car now, does anyone know if the propshaft center bearing can be replaced on it's own or do I need to get a whole new shaft?

 

One complete unit. Sorry.