Whistling from rear while coasting

So I have a strange noise while coasting. It sounds like a human whistling with a bit of wavering in pitch. It seems to be coming from the rear wheels possibly. It is not super loud, can't be heard very well with windows down in traffic.

99 XJ AW4 NP242

The noise only happens after the car has been driven for a while(15+ minutes), while decelerating from around 40 to 15 mph. If I hit the accelerator it goes away, sometimes if I touch the brakes only sometimes it goes away, also bumps seem to affect the noise sometimes stopping it momentarily or causing it to come back. It does this with the engine off and transmission in neutral as well. Shifting the transfer case might affect the noise, but doesn't always. I was thinking possibly wheel bearings, but the fact that accelerating makes the noise stop has ruled that out?

:wow:

My bet would be pinion bearing, followed by wheel bearings.

Thanks old man,

Update: I jacked up the rear axle and got the wheels spinning in drive. Noise is Definately coming from front of rear driveshaft or rear of transfer case. It has a 3 joint front shaft in the rear. sounds like the centering ball is making the noise. A couple months back the rubber seal for it fell out. I'll be ordering a new shaft.

The shaft can be rebuilt for $75-100.

Awesome thanks!

Here are the Spicer part numbers to restore to factory condition:

U-joints: Spicer 5-1310X (need 3)
Centering flange: Spicer 201544X (need 1)
Seal: Spicer 286418 (need 1)

Spicer also sells a greaseable centering flange that doesn't require the seal. Centering ball repair kits are also available from others. I've found the Spicer sealed parts to provide extremely long life on my own vehicles. I would double check the splines in the shaft before you invest in it though. I've found the splines often get sloppy as the miles rack up. I'd also try your local driveline shop/Spicer dealer for a price (even for a new driveshaft). Sometimes the local shops are very good and then you don't have to deal with shipping.

Thanks for the help!
I'm just going to get a new driveshaft since the slip joint is really loose.

md21722 said:

Here are the Spicer part numbers to restore to factory condition:

U-joints: Spicer 5-1310X (need 3)
Centering flange: Spicer 201544X (need 1)
Seal: Spicer 286418 (need 1)

Spicer also sells a greaseable centering flange that doesn't require the seal. Centering ball repair kits are also available from others. I've found the Spicer sealed parts to provide extremely long life on my own vehicles. I would double check the splines in the shaft before you invest in it though. I've found the splines often get sloppy as the miles rack up. I'd also try your local driveline shop/Spicer dealer for a price (even for a new driveshaft). Sometimes the local shops are very good and then you don't have to deal with shipping.

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