Hi all, at my wit's end and looking for suggestions. I think it's the transfer case, but here's the issue. Recently purchased 92 200Tdi with LT77 and LT230, 98,000 miles. Had a moderately noisy throwout bearing when I bought it so when it stranded me on the highway I assumed it was the clutch (yes, I know). Lowered the transmission and transfer case with no apparent issues, replaced the clutch with heavy duty unit from LOF, and problem persists. Pulled right front hub and found swivel ball full of rust, no grease, rusty bearings, broken CV joint. Replaced both side swivel balls, CVs, etc. Test drive had a grinding/whining noise from what seemed to be the transfer case (this was new). Couldn't shift from H to L. Pulled console again, found missing pin on difflock linkage, replaced, same issue. Shift linkage seems to be binding and maybe transfer case not completely in gear? This time pulled shift mechanism, linkages, diff shift housing, cleaned up, couldn't find any obvious issues, reassemble, H-L shift and diff lock seem to work properly now. Test drive and still same grinding/whining. Videos in attached link where I tried to capture the noise. Low speeds around my driveway. Noise seems to go away when clutch is engaged and especially loud when engine braking. Looking for any suggestions/ideas to look at next. Could the CV joint failing at 60mph somehow have damaged the transfer case? Was in H with no diff-lock of course. According to records, both transmission and transfer case were replaced with reconditioned unit in UK in 2016, about 20,000 miles ago. Appreciate any and all help!

200Tdi noisy transfer case

LOF HD clutches cause all sorts of issues with transfering vibrations into the transmission.
I'm about to take the one out I fitted in August and throw it away before it damages the gearbox/syncro gears.

With the LT230 in neutral does it rattle when you are in gear (especially at idle) ?
Does the rattle dissapear when you press the clutch ?

That’s concerning. I really would like to avoid another clutch job for the time being. It doesn’t rattle in neutral and get quiet when the clutch is engaged. I’m wondering if this noise is normal with a new clutch that hasn’t been bedded yet but it doesn’t sound like a slipping clutch to me.

It isn't slipping, the friction material held very firmly against the flywheel andis separated from the drive member by the springs.
The springs absorb any pulses from the engine.
When you take your foot off the pedal the pressure plate pushes the friction plate against the flywheel and the sudden increase in speed is transfered through the springs to the drive shaft of the gearbox.

The LOF clutch cover presses the friction plate hard against the flywheel, the spring don't absorb anything and all that vibration etc gets passed to the grearbox.
The LT77 (and T380) are a compact/complex gearbox and it rattles and vibrates like a bag of spanners, it's a very scary noise ... several small children with tins of marbles and a demented drummer on acid with broken sticks smacking the shit out of many and various dustbin lids.

My 300tdi shakes and pulses less than your 200tdi too.

Hi,

Sorry of no help, but that's a good looking 200Tdi

miktdish is correct in that HD clutches bring out issues in the drivetrain. LOF themselves advise against fitting a HD clutch if your drivetrain (especially the gearbox) isn't in tip top shape.

By "clutch engaged" do you mean clutch pedal up or down?

Thanks, I love the truck. I'd have said the drivetrain is in very good shape, with a new clutch and rebuilt front hub assemblies. I don't know who rebuilt the transmission and transfer case 20K miles ago but no sparkly bits in the oil that I can see. I changed the oil in both diffs as well and they looked good too. And apologies, I was indeed misusing the term engaged; when my left foot was engaged in pushing the pedal to the floor, I supposed that means the clutch is actually disengaging the engine from the transmission.

What has me puzzled is trying to figure out what would make the noise only when in gear and moving. I would think that if it was a propshaft, the noise would still be present when in neutral (or clutch disengaged) and the vehicle is moving. It's also something that started after I did the clutch and front hubs, and all I did with the prop shafts is remove them, grease them, and reinstall.

Have you tried having the car in gear with the transfer box in neutral? Any noise, and if so, in all gears?

You said the gearbox and transfer case were rebuilt relatively recently. This is a bit of not so useful information, but I vaguely remember Mike of BritannicaRestorations, in one of his many LT230 rebuild videos, mentioning that whilst putting everything back together it is very easy to make a mistake... any ways long story short, some gears can be put in the wrong way around, resulting in the teeth only making contact with eachother with about half the surface. The car will still drive and you'd be none the wiser until premature wear has occurred. Just throwing this out there.

I think it is normal for some noises to only occur when in gear and moving - that's a load on whatever is making the noise.

I know this is probably not the advice you want, but if you take the car to a mechanic that is not afraid of lifting it, having it driven by someone whilst lifted and listening very carefully under the car, he might be able to pinpoint the problem a bit closer. Had this done to my fiancee's RR to find that the TQ makes horrible noise, only in reverse, only at a very specific RPM. I would have never guessed it on my own, in driveway.