Unhappy Nasty Grinding Noise

Dear All,

My 1992 Defender 110 200 TDi has decided to develop a nasty grinding sound in Bristol, which is a while away from Cornwall, where I live. Cue epic recovery mission.

Character: horrible grinding, sounds as if two gears are stripping each other/metal rotating against metal. When present, sound comes in waves approx 2/sec, as if it were incurred by rotation.

Onset: over 4 hours continuous driving the M4 50-60mph two days ago. Only driven a few hundred yards since to check if fixed.

Location: Center-forwards from what I can tell, ? from gearbox/transmission area. I'm by myself though so hard to work out.

Present: any speed over 5mph

Proportional to: road speed, I think, in that it's present at speeds >5mph, with the frequency of 'waves' increasing with road speed.

Seemingly NOT affected by: engine speed, acceleration, braking, coasting (with both gearbox and transfer box in neutral), gear selection (gearbox), range selection (transfer box), diff lock selection, steering.


Based on the above, I thought it might be something distal to transfer box, i.e. problem with drive train/diffs/wheel barings/brakes


History/My work so far:

Rear prop: original, new UJs 1 month ago, greased, no play
Salisbury Diff: good level of EP90, no idea when last changed (on the to-do list!)
Front prop: new prop replaced 4 months ago with new UJs, greased, no play
Front diff: good level of EP90, no idea when last changed. I have drained this today, no metal shavings/indication of failure.
Front swivels: left a bit dry (topped up), right ok.
Wheel barings: no play on all 4 wheels when jacked up individually.
Left front disc brake: dandy
Right front disc: unhappy calipers, old problem, I don't think it's got worse, wheel spins fairly easily by hand


Just in case I am wrong:
LT77s gearbox: good level of lubricant, no idea when last changed
LT230t transfer box: lubricant a bit low with a bit of froth on the top, no idea when last changed, took 160mls to top up
Exhaust: secured, no rattles.
Bonnet support: secure


I'm stumped. Quite concerned it's something nasty in transfer box/gearbox, or a layshaft/mainshaft problem (which I would know nothing about), or ?? a wheel baring



Your thoughts much appreciated.

Cheers!

Rich

check front brake pads !! and disk covers !! can loose a pad ! metal to metal !!

check the calipers - the pads wear thru, so the pad drops onto the hub.

Thanks for your replies guys! I checked the brakes, they're fine, as is the handbrake drum.

I got a friend to hoist it up in his garage and run it off the ground - the sound is coming from the Transfer box just bahind where the front prop comes out.

Been having a look at the Defender Parts Manual, trying to work out what it is, baring??

I'm assuming it's probably a transfer box off and take it apart job... I'll let you know how it goes.

Dear all,

Thanks again for your input on this one, this eventually turned out to a loose diff lock linkage which had allowed the diif lock to engage without moving the selector lever. Our diff lock light doesn’t work, and with the lever in normal position we drove on road and broke the diff. I think specifically it was the barings on the front output shaft in the transfer box.

Sourced the noise by using a metal rod placed on various components with the other end touched to our ear!

A second hand box replacement solved the problem!

Rich