advice on strange noise

[animal]

I'm after some advice from those in the know
Basically I've got a strange scraping whirring noise coming from the rear end.
But its not constant.
When I accelerate hard from a stand still I get a loud scraping intermittent sound for a few seconds then it stops. If I accelerate while already moving it doesn't do it. I've noticed it more and louder since fitting my 2" lift springs on Friday. It sounds like its coming from the rear end of the prop shaft where it connects to the rear axle.
The best way to describe the sound is that its a similar sound to a warped brake disc as in its not a constant squeal but it only lasts a few seconds and after that there's nothing until I stop and then accelerate from a stand still again.
Any suggestions as to what it is.
Cheers

[blackpoolsparks]

Putting aside a rear diff issue, which it may well be, this reminds me of a similar thing on my 2nd gen quite a few years ago.
It was simply that I had managed to bend the guard that covers the transfer box and it was rubbing against the drive shaft when I accelerated.
It may be a s simple as that.
???

[slobodan]

Do you have an LSD?

Although that's usually a shudder.

[gwh200]

If everything else checks out, it does sound diff related...is there any vibration...and can you move the prop at the pinion end a bit to much ?

[animal]

Just been out to have anothet look with that advice in mind and it looks like my rear uj on the prop is bugged. About to break. I wiggled it and there's lots of play in the uj. I did take a pic but can't upload it from my phone.
Thanks for the advice . Looks like ill be placing another order with roughtrax this week.

[gwh200]

Coolio...in as much, it's an easy fix.

[slobodan]

Coolio...in as much, it's an easy fix.

I hate UJ's, Must be a knack. (or a press)

[gwh200]

I did all six props, comprising 10 uj's and two sliders in about two hours...I used two sacrificial sockets,a big hammer and some big grips. It's done about 3000 trouble free, vibration free miles since.

[slobodan]

I've got a couple to do tomorrow, I'm hoping if I moan and bit*h enough my mechanic mate will take over.

[gwh200]

Ah yes...the moaning and bitching method...often used straight after the ignoring the noise for six months method.

[BUSHWHACKER]

I did all six props, comprising 10 uj's and two sliders in about two hours...I used two sacrificial sockets,a big hammer and some big grips. It's done about 3000 trouble free, vibration free miles since.

Yep, the red neck way is definitely quicker and easier.

[yoshie]

A 3.5ton shackle has the perfect opening to knock the hardy spicer apart with the socket method Graham suggests.