Does the sound only occur when changing gear, or is it under acceleration? Has your DMF been replaced? How much milage? Do you get any transmission noise in 1st/2nd or reverse? Mine is making an awful sound at the moment but not sure if it is the box or something near the box resonating. Have a look at the video in my post and see if it's similar http://www.jaguarforum.co.uk/f26/bloody-rattle-driving-me-insane-47989.html.
Regards,
Dave

 

Only seems to happen when changing up too 3rd once in gear no noise what so ever.CLUTCH FEELS FINE GEARS SELECT PERFECT AS FOR dmf BEING CHANGED NOT SURE AS I DON'T KNOW THE HISTORY CAR AS DONE 100K

 

Does it happen on changing down to third? Any crunch? If it was a third gear synchro issue down changes would be worse. DMFs can rattle when the clutch is pressed but this should happen across all changes and when idling in neutral. My noise occurs in gear. If it appears during the change with the clutch still on the floor resonance can also be ruled out. Might be worth checking the oil level in the box during the next service (filler plug is at the from of the box, accessed from below with an alan key) just in case the third gear set is at the top of the box. Other than that I'm at a loss. I've heard very little about box issues in the x so I guess it's a case of drive it and see. May also be worth using a 'screw drive stetescope' on the top of the box with an assistant engaging 3rd (but obviously keeping the pedal on the floor, handbrake on and wheels chocked) to see if you hear anything. I'd also advise doing the same with the bellhousing, in neutral, to see if the DMF is rattling. You can also sometimes exagerate the DMF rattle by facing up a steep hill, engaging first and slipping the clutch a little (only for a second or two).
Regards,
Dave

 

Is it straight forward to change gear box oil ?

 

The noise seems to be when changing up to third gear after clutch is released,like i say it only happens very odd times just does my head in when it makes the noise.There is no effect on performance

 

Dave, You asked me in another thread about my gearbox failure,well the answer is that i got no warning i.e strange sounds etc i just put it in first to pull away and nothing happened except for 2 big holes in the housing and gear oil all over the road.The Jag man said a shaft had sheared and sent bits of metal flying around inside which ruptured the gear housing.I know what transmission whine sounds like but i had none of this prior to failure.
It may be worth changing your gear oil and examining the old stuff for any signs of metal.

 

Thanks for the information! I already changed the oil, though that was 60k ago, and the noise has been there since just before. There was no sign of metal etc. think it's probably something external resonating.

Alto, the oil change is easy, plug on the bottom and filler higher up on the front. Capacity is 1.9l. To fill you'll need to get a length of pipe with a very narrow funnel fitted into it and tread it down from the engine bay into the filler.
Regards,
Dave

 

Dave,i have recently changed the oil on my recon gear box due to very stiff changes, i used comma sx75/90 semi synth (not my first choice)but halfords only had 1 bottle of castrol syntrans!! but i can report that my gear changes are so so much better like a new box.
I also applied grease to the selector that sits on the top of the bell housing inside the engine compartment ,not the cure goudy suggests and this also helps.
There are some pics on this site but cant remember where.