Hi all,
A few days ago I took the diff end of the front prop-shaft off to replace the pinion oil seal which was leaking. Ever since doing this I get a single clunk when I go from a closed throttle to accelerating again. I've checked the prop-shaft nuts are tight. I might just be imagining it but it also feels like there's slightly more vibration since doing this.

Could it be the u-joints? The front prop was new less than a year ago but I don't think I've greased it in all of that time. I need to buy a new grease cartridge for the gun later in the week and then I'll do that. Anyone else have any thoughts?

Thanks.

Do you mean you removed the diff pinion flanged end from the diff? I imagine so as you can't change the seal without doing it!
If so, did you re-torque it to the right numbers- either bolt 100Nm or nut 129Nm?
These numbers are critical as they determine the preload on the pinion gear. It they're off you will either have too much preload and a whiny self destructing diff, too little preload and you'll have a vibrating clunky self destructing diff! Guess which one i think?!
As for the UJs, even new ones need greasing after installation. Thereafter give them a shot every time you do an oil change. The perfect time to check the UJs would have been when you had the prop disconnected to do the diff seal as they need to be checked with no load.

Sorry for the bad explanation, that's exactly what I did. I did tighten it back up to the correct torque level for the nut which I have. I've got some new prop-shaft nuts/bolts coming next week so when I replace them I'll check/grease the UJs and recheck the torque level on that nut.

Only other thing I can think of, as you have the nut type.
The nut is a nylock. Did you put a new one on, or loctite if you re-used the original?

I re-used the original nut (didn't put any loctite on it though), I'll get a new nut and replace it.

I took the front prop back off again today and tested it, it still made the noise, it sounds like the noise is coming from the transfer box area. I then put another prop shaft that I had left over on and the noise has gone (for now). I can't think why the noise would still be there without a prop shaft and then go away with a different one?