My XF 3.0 has done 62000 miles and the gear changes were getting lumpy.

So I though I'd try a gear box oil change, 2 hours later what a difference, smooth into gear, smooth changes, early day but very happy so far.

If you try it, heres what I did. Not saying it correct, so check your manual for your procedure I accept no blame.

This is a messy and tricky process, not difficult, just a lot of messing around.

I drained and measured what came out, note the internals drain back into the sump as you drain, so your get about 5 ltr out, the problem is you can only get 2 ltr back into the sump without the engine running. I also removed the oil cooler feed pipe and after filling the sump, ran the engine for about 10 sec which pumped out 2ltr off old oil from the internals. So I managed to change about 7.5 Ltrs out of the 9.5

1) get the car in the air Safely so you can work under it, it has to be level
2) remove the under tray. I had to repair mine, the heat shields were coming lose, so a pop rivet gun did the trick.
3) Do Not drain the oil untill you have removed the filler plug. I had to make a spanner to undo it. A bit of cut down Allen key welded to a 3mm handle.
4) drained the oil about 5 ltr
5) replaced the drain and refilled with about 2.5 ltr that was all that would fit.
6) disconnected the gear box to cooler feed pipe and plumbed that into a container. Had my beautiful assistant run the engine for 10 secs ish, which pumped about 2 ltr out.
7) reconnected the cooler
8) refilled the gear oil as much as possible
9) started the engine (the next steps need to be done with the engine running)
10) pump the remaining oil into the filler hole until it flows out of the filler
11) foot on brake, very carefully selected all gears
12) recheck the oil level
13) fit the filler plug back in, being very carefully not to burn myself on the exhaust.
14) switch off engine
15) confirm you have put the same amount off new fluid in as came out.
16) double check everything is tight
17) clean underside and refit under tray, and then put back on the ground
18) test drive, and hopefully smile to yourself

One final thought, think about how your going to get the oil back in, there no dip stick tube so it has to be pumped in. I used a 3 feet long plastic tube and a old oil bottle with a filling spout. Note you must also angle the tube into the gearbox so the tube is pointing down into it. Otherwise it just drains back down the outside of the tube. I got covered in the stuff