Difference between revisions of "Towing a Jimny"

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(Significantly improved and corrected the guide, especially regarding rules with lever-operated transmissions)
(Added a chapter which explains the reason for the towing rules)
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=== Checking if the vehicle is in 2WD or 4WD mode ===
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=== Reason for the rule ===
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==== Automatic gear box ====
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* It is a well known fact that nothing in (almost) any automatic gear box must be moving while the vehicle is moving and the engine is turned off.
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* This is because of the fundamental design of most automatic gear boxes - educate yourself on this highly complex topic if you really want to understand why.
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==== Manual gear box ====
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* These have an input shaft and an output shaft.
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* The input shaft is connected to the clutch.
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** This shaft rotates whenever the engine is turned on and the clutch foot pedal is not pressed.
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* The output shaft is connected to the small drive shaft between the gear box and the transfer box.
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** The output shaft rotates whenever the small drive shaft rotates.
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*** If the transmission is in 2WD mode, the small drive shaft rotates whenever the rear drive shaft (between the transfer box and the rear differential) rotates.
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**** The rear drive shaft rotates whenever any of the rear wheels rotate.
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*** If the transmission is in 4WD mode, the small drive shaft rotates whenever either the front drive shaft (between the transfer box and the front differential) or the rear drive shaft (between the transfer box and the rear differential) rotates.
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**** The rear drive shaft rotates whenever any of the rear wheels rotate.
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**** The front drive shaft rotates whenever any of the front wheels rotate.
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* The problem with all manual gear boxes in Jimnys is that the gear box oil circulation is driven exclusively by the rotating motion of the '''input''' shaft.
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* So, if the engine is turned off and the vehicle is moving, the input shaft in the gear box will stand still and the output shaft (and some other bits and pieces) in the gear box  will turn.
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** However, the gear box oil will not circulate and those turning bits in the gearbox will soon be starved of lubrication.
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*** This will cause rapid premature wear of those bits in the gear box.
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* This is why it is important to prevent the output shaft in the gearbox from turning while a Jimny is being towed.
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== Complying with the rule ==
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* As can be concluded from the statements in the previous chapter, the situation is much simpler if the vehicle can be shifted into 2WD mode.
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* Therefore, it is important to be certain that the vehicle is in 2WD mode first, before evaluating further options.
  
  
As can be concluded from the above options, the situation is much simpler if the vehicle can be shifted into 2WD mode.
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=== Checking if the vehicle is in 2WD or 4WD mode ===
  
  

Revision as of 05:27, 20 September 2018

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Introduction

  • There can suddenly come a day when your precious unbreakable Jimny might need to be towed for a significant distance.
    • "Significant distance" means anything more than a couple of hundred of meters.
      • So, this story does not apply to situations when your Jimny is being towed off-road for just a few meters or so, just to get it unstuck.


  • You see, there are rules on how (not) to tow a Jimny.
  • Those rules were set by a vehicle manufacturer from Japan called Suzuki.
    • Jimnys were designed and made by Suzuki, so Suzuki should know best what you should (not) do.
  • Suzuki also wrote a comprehensive user manual for your vehicle, which you were supposed to read in its entirety before ever driving your Jimny.
    • The manual contains the rules on how (not) to tow a Jimny.


  • If you do not have original user manual for your Jimny, the wiki article "Manuals and Owners Guides" should prove to be useful.
  • This article gives additional alternative methods on how to tow a Jimny (and how to "prepare" it for towing), while staying compliant with Suzuki's rules.

Warning Icon.pngThis article was written with the best care, attention and intention in mind.
However, no guarantees are made about the validity of any part of its content.
It is exclusively your fault if you damage your vehicle by following any of the procedures described here!
If you want to be 100% safe, then adhere strictly to Suzuki's instructions on towing, as written in your vehicle's user manual.



Rules for towing

The essential rule

  • The essential rule/condition which must be fulfilled is that nothing in the gear box must move (for a significant amount of time / distance) while the vehicle is being towed.
    • Significant amount of time or distance should mean anything more than like 20 seconds or a few hundred meters.
    • This rule is valid for any Jimny with any kind of gear box, either manual or automatic, diesel or petrol.
  • In general situation, any wheel which is connected to the transmission will cause the output shaft in the gear box to rotate while that wheel is turning.


This condition can be fulfilled in three ways:

  1. By demounting the rear propeller shaft only (if the vehicle is in 2WD mode) or both the rear and front propeller shafts (if the vehicle is stuck in 4WD mode).
    • Then you can tow the vehicle any way you like, as no wheel is connected to the transfer box and the gear box any more.
  2. If the vehicle is in 2WD, by placing the rear wheels on special wheel dollies (so that the wheels do not have contact with the ground).
    • Then you can tow the vehicle from behind with the front wheels on the ground and steering wheel unlocked.
  3. If the vehicle is stuck in 4WD, by loading it onto a truck or a trailer and transporting it like a cargo.


Reason for the rule

Automatic gear box

  • It is a well known fact that nothing in (almost) any automatic gear box must be moving while the vehicle is moving and the engine is turned off.
  • This is because of the fundamental design of most automatic gear boxes - educate yourself on this highly complex topic if you really want to understand why.


Manual gear box

  • These have an input shaft and an output shaft.
  • The input shaft is connected to the clutch.
    • This shaft rotates whenever the engine is turned on and the clutch foot pedal is not pressed.
  • The output shaft is connected to the small drive shaft between the gear box and the transfer box.
    • The output shaft rotates whenever the small drive shaft rotates.
      • If the transmission is in 2WD mode, the small drive shaft rotates whenever the rear drive shaft (between the transfer box and the rear differential) rotates.
        • The rear drive shaft rotates whenever any of the rear wheels rotate.
      • If the transmission is in 4WD mode, the small drive shaft rotates whenever either the front drive shaft (between the transfer box and the front differential) or the rear drive shaft (between the transfer box and the rear differential) rotates.
        • The rear drive shaft rotates whenever any of the rear wheels rotate.
        • The front drive shaft rotates whenever any of the front wheels rotate.


  • The problem with all manual gear boxes in Jimnys is that the gear box oil circulation is driven exclusively by the rotating motion of the input shaft.
  • So, if the engine is turned off and the vehicle is moving, the input shaft in the gear box will stand still and the output shaft (and some other bits and pieces) in the gear box will turn.
    • However, the gear box oil will not circulate and those turning bits in the gearbox will soon be starved of lubrication.
      • This will cause rapid premature wear of those bits in the gear box.
  • This is why it is important to prevent the output shaft in the gearbox from turning while a Jimny is being towed.


Complying with the rule

  • As can be concluded from the statements in the previous chapter, the situation is much simpler if the vehicle can be shifted into 2WD mode.
  • Therefore, it is important to be certain that the vehicle is in 2WD mode first, before evaluating further options.


Checking if the vehicle is in 2WD or 4WD mode

Jimnys with lever-operated transfer box (1998-2005)

  • If you have a lever-operated transfer box, shifting into 2WD is a certain-feedback process.
    • This means, if you can physically shift the transmission lever into 2WD mode (or if it is already firmly positioned in 2WD mode), the transfer case is physically decoupled from the front propeller shaft and the vehicle is effectively already in 2WD mode.
    • This means that no additional checks or conditions have to be made or fulfilled.
      • This also means that it does not matter whether the front wheel hub heads have unlocked or not or whether any 4WD lamps on the instrument panel are blinking or not.
      • It also does not matter if the engine is running or not when you operate the transfer box lever.


To conclude:

  • If the transmission lever is in 2WD mode, proceed/skip to the sub-chapter "Options if the vehicle is in 2WD mode".
  • If the transmission lever can not be moved into 2WD mode, proceed/skip to the sub-chapter "Options if the vehicle is stuck in 4WD mode".


Jimnys with button-operated transfer box (2005-2018)

Things are more complicated with these Jimnys, as is everywhere where electronics are present.


If the engine is running:

  • Shift the transmission into 4WD-H mode by pushing the 4WD-H button.
    • The green dash board 4WD lamp should become constantly lit within a few seconds.
  • Then shift the transmission into 2WD mode by pushing the 2WD button.
    • The green dash board 4WD lamp should turn off completely within a few seconds.
  • After this is performed, there is a 90% chance that you are now truly in 2WD mode.
    • However, if you want to be 100% certain (because electronics can sometimes get confused), perform the procedure "if the engine can not be turned on" below.
  • Proceed to the sub-chapter "Options if the vehicle is in 2WD mode".


If the engine can not be turned on:

  • Jack up the vehicle so that either the left or the right front wheel is completely raised from the ground.
  • Then turn the raised front wheel by hand and see if the propeller shaft is turning as well.
  • Lower the vehicle.
  • Repeat the same procedure with the other front wheel.
  • Now, if neither of the front wheels are turning the front propeller shaft, the vehicle is truly in 2WD mode.
    • In this case, proceed/skip to the sub-chapter "Options if the vehicle is in 2WD mode".
  • However, if either (or both) of the front wheels are turning the front propeller shaft, the vehicle is not in 2WD mode.
    • In this case, proceed/skip to the sub-chapter "Options if the vehicle is stuck in 4WD mode".


Options if the vehicle is in 2WD mode

There are three possible options:

  1. Demount the rear propeller shaft from the vehicle (a rather simple unbolting job).
    • Then tow your Jimny any way you like.
      • This means that all four of its wheels can be on the road, and you can tow it either from forward or from reverse side.
  2. Place both rear wheels on "dollies" (small platforms on small wheels) so that the rear wheels do not turn while the vehicle is being towed.
    • Then tow the vehicle from behind, with rear wheels on dollies, front wheels on the ground, steering wheel unlocked.
  3. Load the Jimny onto a truck or a trailer and have it transported like a cargo.


Note Icon.pngIf demounting the rear propeller shaft, don't forget to first mark its exact mounting positions in relation to the transfer box and the rear differential.



Options if the vehicle is stuck in 4WD mode

You have two options on how to proceed:

  1. Manually decouple the front wheels from the transfer box in order to effectively "restore" 2WD transmission setup to the transmission system.
    • After you do this, you can perform any of the procedures from the sub-chapter "Options if the vehicle is in 2WD mode".
  2. Load the Jimny onto a truck or a trailer and have it transported like a cargo.


Manual decoupling of the front wheels from the transfer box can be performed in one of the following two methods:

  1. By demounting the front propeller shaft (a rather simple unbolting job).
  2. By demounting the wheel hub head from each front wheel which has been found out to be turning the front propeller shaft (a rather simple unbolting job).
    • Then and manually slide the collar in the wheel hub head all the way inwards.
    • The wheel hub head is now in a "free" position and can be returned back on the wheel, and that wheel will be disconnected from the drive line.
      • Beware that you should not try to turn the engine ON after returning the unlocked wheel hub head(s) back on the vehicle, as the vehicle computer might automatically try to lock them again as soon as the vehicle is turned on!

Note Icon.pngIf demounting the propeller shaft(s), don't forget to first mark their exact mounting positions in relation to the transfer box and differential(s).


Note Icon.pngIf demounting the the front wheel hub head(s), don't forget to first mark their exact mounting position in relation to the wheel hub(s).




Page last edited on 20/09/2018 by user Bosanek