Hi,

I have just bought a 2001MY XK convertible with 130,000 miles on the clock. Great condition and from a good specialist Jag dealership near London. However, I'm getting an intermittent grinding sound from the rear right (driver's side in the UK) when doing between 35 and 50mph. It is very loud and could almost sound like a brake bad skimming the disk, but the sound sounds deeper and more internal than a brake disc. It doesn't seem to be the parking brake either, and it only occurs between these particular speeds.

The garage I bought it from are checking it over and can't find fault. Their suggestion is changing the gearbox oil, which needed doing anyway, but I'm not convinced this is the cause of the problem.

Any thoughts on what it might be and how to help the garage diagnose it?

Cheers,

Stephen

 

You are not alone. See the thread from Dewzeexk8 on the same problem. Not resolved yet, but sounds like you guys might be chasing the same problem.

https://www.jaguarforums.com/forum/x...xk8-54k-88617/

 

My XK8 only makes this noise when under a slight load -- never just coasting

Grinding Noise between 32-40 mph on 97 XK8 54K

 

I used to get a noise due to the gear oil being low. It started out as a grinding when the car changes up a gear 2-3 or 3-4, but as it became progressively worse the noise was pretty much continious at 30-50 MPH .

Alternatively, I used to have a Skyline with a similar problem. In my case, it was caused due to the pins holding moving part of the rear breakes being warn down, allowing the assembly to wiggle ever so slightly... at certain speeds this resonates cosing a really loud noise. Pretty much anything can cause this type of resonance noise, for example, perhaps the fuel pipes running on the right hand side of the fuel tank need fixing down? Good luck!

 

I had a noise in the rear on my '97 and diagnosed it by (carefully) hanging a wired microphone and a portable minicassette recorder first near each brake and then near the differential. The noise was significantly louder at the diff. The previous owner had a gearbox leak for who knows how long and did nothing about it. Luckily for me at that time I had an xtended warranty. They replaced the whole rear-end and went out of business a month later. That old recorder has ID'd many problems since and something similar may help you get in the right area at least. Jac

 

This is resolved. The garage changed the gearbox oil and the sound has virtually disappeared now. It turned out that the gearbox had been filled with transmission fluid, rather than the official oil, which had begun to breakdown quicker than the correct oil. A lot of very expensive oil later and not only does the gearbox sound so quiet, but the gear changes are barely noticeable and the grinding sound is gone. I can still faintly hear the gearbox working harder at those speeds, but nothing out of the normal.

 

By Gearbox Oil are you referring to the differential oil ? I have an automatic tansmission and I hope it has the proper fluid !

 

No, I mean the gearbox oil. They are sealed for "life" but life means about 50,000 miles. Mine had clearly been refurbished at some point (probably under 80K miles) and it is now on 130K miles and they had not used the exact oil required. You will need about 14 litres in total and at about 30 quid a litre you can do the math... Anyone doing a gearbox oil change for you on the cheap won't be using the right (best) oil. Just find a good specialist who know what they are doing so they use the right fluids.

 

Holy crap... I thought I was the only person to do this !!!! I'm surprised more shops do not have a multi-mic or multi-piezo (vibration) sensor kit setup. Ya wanna find out where that annoying sound is coming from???? put a freaking 10 channel mixer on it.

 

Holy crap... I thought I was the only person to do this !!!! I'm surprised more shops do not have a multi-mic or multi-piezo (vibration) sensor kit setup. Ya wanna find out where that annoying sound is coming from???? put a freaking 10 channel mixer on it.
We are clearly brothers from different mothers.