help with squealing/grinding driveline?

[snelson]

Hi again all. I posted here a while back about what I thought was a squealing sound caused from shifting into 4X4 on the fly. But I think the squeel must be something else.
It's happening in either 4H or 4L.
I was just hoping that perhaps the group could give me some suggestions on what it could be.
The toughest part is that it's intermittant, so hard to bring into a shop when it's not a constant sound.

So - it's a high pitched squeely sound, sometimes metallic grindy sound
Is not effected by engine speed
Is not effected when I use the brakes
It's a pulsating sound, so squeaks as something is turning but I can't determine if its wheel spin or driveshaft
Sound is there in 4H and 2H
The sound comes and goes - arrrgh
There's no clunk when starting or shifting from P to D
It's not a sound coming from the engine, only hear it whe the tires or driveshaft is moving/spinning.

Any ideas at all? Its so tough when its intermittent but its to the point now that I'm tense driving all the time cause I don't know if its something serious/critical - or just something small.
Any suggestions much appreciated guys
Thanks
Steve

[Sabb]

Absolutely no expertise, but it sounds a lot like a seized wheel bearing I had in another vehicle--the intermittent squeal grew more regular, as I did more damage (hub, rotors etc) Can you localise it to one corner of the van?

Sabb

[quadzilla]

snelson - I was having a similar problem while driving / accelerating. See http://www.delica.ca/forum/strange-sound-4192.html

Recently learned that the turbo bearing is hitting the impeller under acceleration. This may be your problem as well. Some other good suggestions in the post as well.

Good luck.

[CVI]

Maybe you've checked this already but....check the front brake pads. They have a sensor that squeals irritably when the pads are low. And will be intermittent if the sensor just touched the rotors. It's a steady squeal irregardless of speed. Just a quick check before anything else.

[snelson]

Thanks for the suggestions so far guys.

Hubs - I'm going to replace the hubs with manual ones, so I'll see if this cures it.

Turbo - I don't think it would be the turbo, I can rev the engine in park or neutral all day long and can't replicate the sound. But the minute I start to move, I hear the squeal/grind.

Brake Pads - This could be it too, but does the brake sensor sound go away when you engage the brakes? My sound is still there when riding the brakes. Can't define exactly where the sound is, I've walked along side while the wife slowly drove, but sounds like it's coming mid cabin.

One other possibility from Quadzilla's post - universal joints. Do these squeel/gind though? I thought they really just made a clunk when shifting into drive....?

Thanks again guys, would love to hear any other possibilities...
Steve

[Golf Cart]

Turbo

One other possibility from Quadzilla's post - universal joints. Do these squeel/gind though? I thought they really just made a clunk when shifting into drive....?

If the U-joints have dried up they will chirp. If the U's havent been serviced ( re-greased ) on a semi regular basis, they will dry up. Submerging in water is another culprit. Water gets into the cup and sits there, and will slowly rust out the needle bearings. The needle bearings will rust until they develope a flat spot and will stop rolling. I've found this out on my Ford. The front U's on my 4x4 were the culprit. Give the main U's 3 or 4 shots of grease and see if it shuts the noise up, or at least quietens the noise up.

Good Luck