Vibration on overrun

So I knew all was going too well! Did 45 miles yesterday, as usual avoiding motorways as the Normally Asmatic isn't keen, I start to get a rumble and vibration when I'm just on a neutral throttle, seems to be from the back, it's fine on or off throttle, I stopped and checked both diffs and t/b oil levels, all are fine, I only changed the oil recently, I even did the journey home with the centre seat panel removed hoping to hear some tell tale noise (I'm now deaf in my left ear but it was a nice warm ride home) Once home I checked the prop joints, all have been recently greased but I re do them, the only slop I can find is in the sliding joint on the rear shaft and that's only if I pull the shaft up and down, seems to be no rotational play at all, when I grease this joint the grease comes out behind the front u/j none comes out around the collar, is this normal? I've read a few posts on here about similar problems and most seem to suggest the prop, just wondered before buying one if anyone had a diffinitive answer? The rear axle is a Salisbury so I'm hoping it's not the Diff as it looks more of a pain to sort than the other types.

You could try taking the prop off, putting the centre diff in 'lock' and going for a little drive to see if it sounds any different. The fact that you can wobble the splined section up and down suggests that there could be some movement (and hence noise) whilst the prop is in use. There's not much to do other than buy a new one. The spiders and bearing caps in the universal joints can be replaced, but you can't just buy a kit for the splined section I'm afraid!

Brown said:

You could try taking the prop off, putting the centre diff in 'lock' and going for a little drive to see if it sounds any different. The fact that you can wobble the splined section up and down suggests that there could be some movement (and hence noise) whilst the prop is in use. There's not much to do other than buy a new one. The spiders and bearing caps in the universal joints can be replaced, but you can't just buy a kit for the splined section I'm afraid!

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Well I'm back under it again now and there is some rotational play in the sliding joint, also banging the shaft with my hand creates a distinct knock knock, suppose amplified by chassis and ever vigilant ears it could well be the noise! Off to the prop shop I shall go, I'll report my results, thanks for your help.

Recently changed my front prop for the same reason.

Seems as though the prop is past it anyway. Am I right in thinking you have been pumping grease into it until it's coming out the end?, as far as I know they only need a couple of squirts every now and then, you can easily over do it and if there is that much grease in the tubular part it can unbalance the whole lot.

So as a follow up I eventually got to fit the new prop, disappointing to note that the new prop has about the same amount of play in the sliding joint as the old one but after removing the old one it turns out to have a near siezed rear UJ (it will move if I use a hammer) this is despite new grease having been pumped in and finding it's way through the bearing! So now just a couple of wheel bearings to sort. Thanks for all the help.

Rear prop caused some weird over run vibes on my series, new prop sorted it.

Trouble with a siezing UJ's is the grease goes to all the journals but the one that needs it