Gearbox Parking Brake Damped Brake Drum - TRANSMISSION DAMPER - 275239 From SII - 2 Litre Diesel LWB 109
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Does anyone know why the TRANSMISSION DAMPER - 275239 was only fitted I believe to the SII 2 Litre Diesel LWB 109 ?

Any advantages in fitting the TRANSMISSION DAMPER to SWB 2 Litre Diesel or even SWB/LWB Petrol Series Land Rovers ?

Thanks

There is some mention of this in James Taylor's book, but I don't have it to hand to check. First time I've actually seen this damper in the real world!

I have a few of these NOS dampers in their original red and yellow Rover boxes.

They weren't just fitted to SII diesels, but were fitted to Series One 109" Diesels from the start.  (I have one).

Rover struggled with NVH on the 2lt diesel from the moment they mounted it in a vehicle, and made various alterations after they were launched, to lessen this.

Which particular problem surfaced on the 109" diesel, I don't know.

But whatever it was, it was clearly solved by the time of the 2.25 diesel.

NVH, Exile?

Quote from: simonbav on Oct 04, 2024, 07:20 PMNVH, Exile?

Noise, Vibration and Harshness

Years ago I fitted one to a Series II petrol - I can't remember why now. It do remember it made a big improvement to the gearbox, in smoothing out gear changes. I could never understand why they were not fitted as standard.

Quote from: Exile on Oct 04, 2024, 05:26 PMI have a few of these NOS dampers in their original red and yellow Rover boxes.

They weren't just fitted to SII diesels, but were fitted to Series One 109" Diesels from the start.  (I have one).

Rover struggled with NVH on the 2lt diesel from the moment they mounted it in a vehicle, and made various alterations after they were launched, to lessen this.

Which particular problem surfaced on the 109" diesel, I don't know.

But whatever it was, it was clearly solved by the time of the 2.25 diesel.

I imagine something to do with the length of the rear propshaft and resonance ? I have considered trying one on my 88" diesel if I ever come across one, just to see if it made any difference.

I remember wondering what various components were under my Range Rover LSE when I first got it. There was a random bar of steel sticking out the back of the swivel housings and a round metal disc thing with a cable on it mounted to the front diff.

Later learned they are harmonic dampers and fitted to tune out vibrations of a certain frequency.

I once worked at a company that made hybrid Diesel / electric busses. We made a generator with a 1.9 Diesel engine driving a 1:2 gearbox onto an AC generator. The noise from that gearbox was horrendous until we fitted a very large flywheel onto the engine to damp the motion of the crankshaft. A high compression Diesel engine crank accelerates each time a cylinder fires and slows down each time a cylinder comes up to compression. If you can't damp that motion it gets transferred along the driveline.

Never seen or heard of the handbrake drum damper though, interesting thing.

Craig.

The 200 & 300 Tdi engines also had their problems but this was due to the resonance created by the fact the engine & power train is like a dumbbell, two masses connected by a relatively flexible middle connection ie the clutch housing and gearbox bell housing. Various strengthening features were made  over the years. The mass of the parking brake bolted on the back end didn't help and it was one consideration for going to rear wheel park brakes on RR and D3

The damper is damping the rotation of the 109" propshaft, not the engine, so presumably it is something to do with forward motion, rather than engine revolutions.

All 2lt diesels have a damper on the front of the crankshaft, but the transmission damper is unique to the 109" 2lt diesel so the problem, whatever it was, did not affect 88" diesels, or any 2.25 diesels.


There must be a reference to it in the literature somewhere, but if so, I haven't seen it.

Some things haven't changed. Have a look at the back of the transfer box on a LR with a DT5 engine fitted. There's a huge lump fitted there to combat a similar NVH issue.
Then go and look at the back of a Discovery 4 chassis and look how much metal is winging about above the exhaust near the rear cross member. Again to deal with NVH. Typical Land Rover - add weight to make the noise go away...