Towing a Jimny, is the owners manual wrong?

Bosanek wrote:
By the way, when did the R72 gearbox "arrive"? Was is at the same time with the push button transfer box or was it before?

Yes, The VVT/pushbutton came with the R72.
M13a nonVVT have the earlier gearbox and lever transfer box
.

Bosanek wrote: Or could it be that even types 1 and 2 are susceptible to those rules as well, but that Suzuki just had not thought of those issues before 2002?

This I think. Very few cars get towed any significant distance in their lifetime. It would have taken several people towing them significant distances behind motorhomes before the issue showed itself.

Find it very strange that lubrication has not been "thought of" in a gearbox.
That is why I think more it could be an unforeseen heat issue.

I work with designing gear boxes for ships and when we have settled the rpm and torque, gear set, chosen bearings for it, the most important thing we think about is lubrication, drainage and circulation of the oil, and lubrication... did I mention lubrication?
Then cooling.

But then again assumption is the mother of all f#¤%-ups

Someone expressed concerns about gear box lubrication when a Jimny is coasting in neutral (like when approaching a traffic lamp).

If my thinking is correct, that is not an issue, as the engine is running, the gear box is in neutral, and the clutch foot pedal is not pressed.

So the input shaft in the gear box is connected to the engine through the coupled clutch and is therefore rotating all the time. As the rotation of the input shaft is circulating the gear box oil, it's all right then to coast in neutral?

If this is correct, than a Jimny could be towed any way you like in 2WD transmission mode, as long as the gear box is in neutral and the engine is ON all the time, right? But then, it is a rare occurrence that a vehicle, which has to be towed, has a working engine ....

yakuza wrote: Find it very strange that lubrication has not been "thought of" in a gearbox.

I work with designing gear boxes for ships and when we have settled the rpm and torque, gear set, chosen bearings for it, the most important thing we think about is lubrication, drainage and circulation of the oil, and lubrication... did I mention lubrication?
Then cooling.

In the automotive world it is

1) make it as cheaply as possible
2) make it just last out the warranty
3) buy the parts from the cheapest possible supplier

The gearbox is designed to lubricate itself when it is in normal use, towing with a dead engine isn't normal.

Bosanek wrote:
If this is correct, than a Jimny could be towed any way you like in 2WD transmission mode, as long as the gear box is in neutral and the engine is ON all the time, right? But then, it is a rare occurrence that a vehicle, which has to be towed, has a working engine ....

Correct. And I imagine over short distances (say up to 10 miles) it is very unlikely to be an issue even if the engine is off. It's certainly not something to ever worry about in normal driving situations.

Well, the "critical" distance is a matter of debate. I am no gear box expert, but I assume that the critical distance would more likely be in the domain of several hundred meters or a few kilometers at most.

If it were as much as 10 miles, the manufacturer would probably have written that towing is OK for certain relatively short distances.

But others might disagree on this assumption.

So does this mean that (my bad habit of) coasting down hills in an attempt to accumulatively save fuel is damaging the car?

Max Headroom wrote: So does this mean that (my bad habit of) coasting down hills in an attempt to accumulatively save fuel is damaging the car?

Bosanek wrote: Someone expressed concerns about gear box lubrication when a Jimny is coasting in neutral (like when approaching a traffic lamp).

If my thinking is correct, that is not an issue, as the engine is running, the gear box is in neutral, and the clutch foot pedal is not pressed.

So the input shaft in the gear box is connected to the engine through the coupled clutch and is therefore rotating all the time. As the rotation of the input shaft is circulating the gear box oil, it's all right then to coast in neutral?

If this is correct, than a Jimny could be towed any way you like in 2WD transmission mode, as long as the gear box is in neutral and the engine is ON all the time, right? But then, it is a rare occurrence that a vehicle, which has to be towed, has a working engine ....

I think Bosanek here got it right.
Also if you keep the gearbox in a gear while coasting but clutch depressed the lube should be sufficient.

I remember hearing a strange metallic rattle under the car when for example sliding down from ramp after maintenance(engine off). Never heard this noise with the engine on. Not sure if related?

muto wrote: I remember hearing a strange metallic rattle under the car when for example sliding down from ramp after maintenance(engine off). Never heard this noise with the engine on. Not sure if related?

There is no chance that is related.

Lets be clear here. We are talking about ball and roller bearings encased in a box half full of thick gloopy oil. They won't sustain any damage in the very first instance of being rotated without positive lubrication. In fact when running under no load (coasting, being towed etc.) they require only the merest hint of oil to provide sufficient lubrication. It's very different to, for example, an engine running with no oil, where plain bearings (essentially metal on metal, save for a thing layer of pressurised oil) are continually under very high loads.

This is why I made my point about it being very unlikely to cause harm over short distances and in general use. For 99% of Jimny owners it is not an issue. But if you are thinking of towing your Jimny 1,800 miles to the South of Spain behind a motorhome then then it is definitely something you should consider.