Loud screeching noise - help please

Any expert out there help me with this? I have a Series III diesel landrover which I rebuilt on an new chassis a couple of years back, so I figure I know my way around, but this has got me stumped.

Normally all is fine but from time to time, when I reach about 45mph there is a really loud screeching/grinding sound - like metal against metal, which then won't go away until you almost stop. Varies with the speed of the vehicle not the engine. I have checked all the usual things - oil levels, rear diff (not the front as it happens with the free wheel hubs disengaged), prop shaft, the shims on the intermediate gear in the transfer box. Happens in top gear, overdrive in or out, over-run or under power. Won't go fast enough in low ratio or other gears to make it happen.

I could just try ignoring it and wait for something to break, but I'd like to know where to look next before I get stranded somewhere. Anybody got any ideas? Sounds like the noise is coming from the gears but not sure about that - the whole thing is shaking once it starts.

All advice gratefully received.

Percyatok

I'm going to plump for hardy spicer spider joints in rear probshaft.

Thanks for the rapid suggestion but I alreadychanged those - it made no difference!

Percyatok

clutch etc ok? could be a release bearing or something

I'd wondered about that, but depressing the clutch makes no difference - just rolls to a hit still grinding away just the same. If the gearbox has to come out I'll replace it anyway just in case, but I don't want to pull the gearbox out unless I am sure it is something I can't get at from elsewhere. It was so much easier getting the gearbox in when there was no bodywork fitted, now I can see it is going to be a horrible job!

wheel bearings or maybe yer freewheel hubs

a wheel bearing perhaps?

I had a similar problem coming back from spain a few years ago, but we kept going, it turned out to be the rear diff, oil had leaked out and the drive wheel expands with the heat and rubs against the diff housing, in the end it cut a hole right through and the back axle locks up. Just a thought.

p.s. that was in a 110!

lets face it it could one or more of many things, unless you drive it and listen all you can do is take a guess based on our own experiences. we really need sound on here, rather than just a written grind,whine,grunt or groan

hay do you think they could put that in, would be really good to be able to hear stuff, wouldnt help me find what the fault is, i'm rubbish, but others could!!

well not so long ago some one had a noise that they said came from the clutch g/.box area.. turn outs it was from the top of the engine. so maybe it would help...if ,the sound quality was good enough

yeah but then everyone would have to buy microphones, hmm... maybe it not such a good plan!

oh dear!! i could sell you microphones for a couple of squid each. not too much if it helps people help you. but then again there is enough people here so that one of us should come up with the right answer..
well its back to "my landy makes a kinda skaboom wheee hiss noise" and i think its coming from somewheres up near the front left hand headlight when i'm in low range second gear going down a 10° hill with the wind at an angle, to the front of the landy of 45.856°. it also does it when i'm in bed at night. could this be the diff or has the neighbours cat got stuck again

Than for all the advice guys - just taken a look at the offside front wheel bearing - inner race lubricated more with rusty water than grease, so that's the favourite target now. To be fair to me it is in the same direction from the dirver as the gearbox! Never heard a wheel bearing scream like that before, but I suppose in a Landy you wouldn't hear the usual warning rumbles above all the other racket.

Another Idea for you. Is the handbrake drum may be lose. This would give you a loud noise and make the whole thing rattle. Just an idea...

Another one to do is jet some good axel stands make sure the vehicle is up off the ground at the back and cant fall off or over and drive it up to 45mph when it starts get out and listen around for it. Just make sure its solid and going nowhere. Would not want to hear about it setting off down the road without you in it...

You havn't got a pig in the back and forgot to feed it, [just a thought]. . .

Thanks for all the helpful suggestions (and the rest). Having changed the offending wheel bearing I have now done 100 or so miles with no trouble so I guess it is sorted - until the next time!

Nice one mate. Not alot of ppl come back and say thanks. Glad you got it sorted....Another landy thats not destin for the scrapyard