Jaguar Repair Problems? Ask a Jaguar Repairs Expert.
When you say thudding is it like a clunking sound? When do you hear the noise?
OK based on your description it sounds like the noise is coming from the center support bearing on the drive driveshaft. Unfortunately these are not serviceable so the complete shaft may need to be replaced. Let me know.
Yes the complete shaft and center support is visible from under neath so it can be checked. The shaft is about $700 new from Jag and about a 1-1.5 hour labor charge.
Of course it can be something else in the driveline. Without hearing the noise it is hard to say. Try contacting this shop to see if they can assist. http://gmwhawaii.com/ $3500 is a pretty good price but I an tell you that the 2003 X type may not be the most reliable vehicle and can be costly to repair.