How to drive Jimny in 2WD in Low mode of transfer case?

This mod should also work on the current-gen Thar.

BHPian purohitanuj recently shared this with other enthusiasts.

Why do it?

As Jimny has a part-time 4WD, you cannot use it on high-friction roads which require steering inputs. Consider the Sandakphu track which is now cemented, with steep gradients and very acute turns. Hence, one cannot engage any of the 4WD modes available. And the grunt at the initial pick of this 1.5L NA engine is way too little to get it moving from the steep slope.

Another great topic to see the reason and other technical bits is here: (Review: 1st-gen Mahindra Thar (2011 - 2019))

Transfer Case to the rescue!

Imagine a world where you can put Jimny in 4L and disconnect the front wheels. Now you can steer as much as you want without thinking of and windup in gears. This would have been possible if Jimny had freewheeling hubs; which it does not.

So let me explain the 4WD system of Jimny a bit. There is a transfer case which has 3 options (actually it has 4, but let's focus on 3)

1. 2H
2. 4H
3. 4L

In 2H, the TCase output shaft and input shafts are connected in a 1:1 ratio ( for simplicity here but in reality it's 1:1.32).

The Tcase has 1 input shaft and 2 output shafts. 1 of the output shaft goes to the rear differential and 1 to the front. The rear output shaft is always connected, but for the front shaft, there is a mechanical mechanism which slots the front output shaft into the drivetrain.

This happens when you pull the lever to 4H; i.e. the front shaft from the transfer case to the front differential engages.

This mechanism helps in maximising efficiency as in 2H, your engine is not rotating unwanted components.

Ok which this done, the front axles in the shafts are also rotated which are connected to both ends via the differential; but these are not connected to the tyres yet.

Why So? Consider if they had been connected, then in 2H, the tyres would have been rotating these shafts and hence again decreasing the efficiency and also more wear and tear.

Thus there is a way to attach the tyres to the axles.

This is where the hubs come into play. There are many ways to lock the wheels to the axles like electrically actuation; Jimny has Vacuum-assisted hubs. In this technique, the engine produces a vacuum which literally sucks a diaphragm and moves the teeth of the wheel hub closer to the axle teeth and interlocks them.

As this method is dependent on engine vacuum, which is a function of atmospheric pressure, hence you will find Jimny struggles to lock its hubs in high-altitude regions. You will need to rev the engine to lock the hubs in those regions. A blinking 4WD light in the dashboard lets the driver know that the hubs are not yet locked.

Now coming to the main topic, we can get away with disconnecting the front hub locking mechanism, we can make sure that the front wheels do not lock to the powered axles.

This is where the crux of the above mod comes in. There are two solenoids which are responsible for enabling/disabling the flow of engine vacuum. If we can cut the power to these, the Jimny would effectively be in 2WD always.

This is like keeping the freewheeling hubs in 4x2 mode with 4WD applied.

How do we do it?

It's simple, just pull out the fuse 24 from the front fuse box in the engine bay.

After you disconnect the fuse and start the car, the car will tell you that the ESP is offline and a check engine and check transmission light will be on. This will go away if you replace the fuse and drive for 30-40 minutes in 3-4 engine cycles.

This video shows me driving in 2H on a tarmac road with 30km/hr at 3000 RPM and then in 4L with the fuse removed (effectively in 2WDL) on the same tarmac with 15km/hr at 3000 RPM. The steering is as it is in 2H and I can use and turn it anyway.

This is the video

After putting the fuse back, I had the engine check light and transmission error light lit up on the dashboard. All other errors were gone. The car drove normally, the 4x4 system worked perfectly, and the Aircon also worked fine.

After driving around the car for 40-50 minutes and with the cycling engine on or off 3-4 times, the dashboard MILs also went away.

I then hooked up the ODB scanner to see if there were any pending codes, which as expected were 0.

Hence, I think this is a good way to engage 2WD Low in cases where it's applicable; and revert Jimny to its default driving conditions.

Some of the examples where one would want to do it:

• Hatu peaks in summer.
• Sandakphu
• Towing a vehicle on roads.

This mod should work on current-gen Thar as it has electronic locking front hubs and a mechanically locking Tcase. It will not work in (some ?) Gurkha as it comes with always locked front wheels ( hence the 4x2 and 4x4 high efficiency is almost the same)

Fulltime 4wd and AWD are different and not be confused here.

Hope I was able to explain this enough. Bye cheers!.

Disclaimer: Use it at your own risk and if you understand what is happening and when required for short time.

Check out BHPian comments for more insights and information.