Re:That super short grinding noise in first gear...

I have two comments on this theory of the clutch being the source ...

First - the noise would not be present on the automatic transmission models, and whilst it wasn't on the automatic I've driven, IICIIEII says it's there on his, and second, if it does come from the clutch why would be it clearly felt in the transfer case shift lever and not in the gear shift lever, which is what I have experienced.

I have a manual one! But based on my experience with noisy clutches it does not sound much like the clutch to me, also I clearly hear it on the back. That said, my rally car is a DIESEL Golf MK4 with ceramic clutch and single mass flywheel. The noise of the flywheel alone in idle would mask any other noise, not to mention the noise from the engine. This is a very different scenario, so who knows.

Ok, I will try again to explain how plausible this is..

Every single item in a driveline will oscillate at strain at a given torque load and rpm. When designing such items, a calculation of the inertia will present at wich rpm differnet items inner oscillation frequency will coinside or get enhanced by the vibratory torque. The total system coupled and uncoupled is calculated. If unlucky one must avoid certain rpms or make changes like move the bearings around, make the shafts thinner or thicker to dampen the vibrations, or whatever will make the vibrations occur on rpms above or bellow the critcal places.

In an auto there is a differnet distribution of torque and the masses of the driveshaft and everything turning is different so there is a competely different picture.

On my car this noise began to occur when I moved alot of the transmitted torque from elsewhere in the driveline to the transfere case by gearing it down as I changed the gears driving the chain, and also using new gears and an old chain would not help.
Taking off with less torque makes it go away, taking off uphill or wiht a loaded trailer makes it worse. A pattern that (to me) explains the noise and how it behaves.

From all I have read of the Gen4 noise and the service bulletin it all makes perfect sense.

The workshop technician that was quoted up here somewhere saying that a lift would make it worse is at best unprecise. A lift would not change how torque is distributed in the system, but larger diameter tires could, just by changing the final gear ratio.
But just a lift, sorry i cannot see how the minor change in drive line angle could make such a difference.

The inertia of each item will affect the system vibratory torque and behave like either damper or an enhancement in the system, depending on each items mass, diameter and placing. The more mass or the larger diameter, the more the item will affect it. A large volume of rubber is often a good thing but it all depends on the total picture.

Most of us ( ) have experienced the steering wobble i guess, it is a bit like the same thing. Very small items with very small mass trying to dampen the movement of the much larger tyre.

Hoping not to have confused people more

Tonka developed a judder on take off, so I rang the dealer and he had the car in for a day to investigate. When I collected her, the manager advised me that Suzuki would not agree to paying for any work as the car had been lifted. I asked for a quote to investigate the problem and was told to expect a bill for circa.£1,600. Suppressing a desire to laugh I thank him and left. On the way home the judder disappeared and has not returned.
Anyway, back to the T.Box .My SJ had a gear driven box with a neutral position. This allowed me to tow the SJ on an "A" frame without damage to the gearbox. This is in itself - in my opinion - a good point as was the fitting of a separate hand-brake to the output flange of the box. Why then did Suzuki design a box with a chain drive that has a problematic chain, no neutral so you can't/shouldn't tow unless you remove the prop-shaft and no separate hand-brake.

Roger

wrote:

<snip>
Why then did Suzuki design a box with a chain drive that has a problematic chain, no neutral so you can't/shouldn't tow unless you remove the prop-shaft and no separate hand-brake.

Roger
 

The chain is quieter, most 4x4s with luxury pretensions are chain drive.

As to why no neutral, the gen 4 has a built in neutral- if you don't use a hammer to ensure that it is actually fully in low

My old RangeRover had a chain drive epicyclic transfer box, I'm fairly sure the transfer lever had a neutral, but there was no 2wd/4wd selection to deal with like on the Jimny.