[Blooming Flower]

Originally Posted by purohitanuj

Intuitively, one would think they are driving in 3WD, but even freeing up one wheel will effectively make it 2WDL.

As I read on the posts here I searched through and zoomed in some photos from the archives of my several Sandakphu trips in the past.

Interesting finding is, the local drivers only install a single FWH at the right side front wheel for Bolero or Thar Di. See the attached pic. Nevertheless, during my trips I never noticed this consciously.



The reason is also decipherable from this.

Why single FWH = Cost effective
Why right side only = Easy to access for the driver.

Day-in day-out, heavy duty 4x4 vehicles like the Bolero 4x4, Thar, Landrovers are pulling 7-8 pax. along with luggage on the roof in this route.

One thing is quite clear, the local drivers might not have a theoretical knowledge of PAW (permissible axle load), torque transfer, axle twist etc. But they have the feel for the mechanics of these vehicles. First 80% road from Maneybhanjan to Chitrey is tarmac-topped, next from Chitrey to Gairibus is concrete, and the last few kms are bouldered, steep, real 4x4 track.

As the local drivers are very well versed with the track there they know where to engage the FWH and where to disengage it without compromising the safety of the passengers as well as the drivetrain of the vehicles.

[Samurai]

I think Sutripta has summed it up perfectly in the earlier thread.

https://www.team-bhp.com/forum/4x4-t...ml#post2994995 (Using 4L for Engine Braking/Torque with FWH Disengaged)

[Blooming Flower]

Originally Posted by Samurai

I think Sutripta has summed it up perfectly in the earlier thread.

https://www.team-bhp.com/forum/4x4-t...ml#post2994995 (Using 4L for Engine Braking/Torque with FWH Disengaged)

Absolutely. I referred to this post while discussing my use case and reason to replace a perfectly working auto-locking hub in my Thar with some off-roading fraternity. BD sir advocated what should be done from OEM perspective and Sutripta da has given the most sensible reply in that thread perfectly summing up all the aspects of 2WD-L mode. This is the reality in today's date at north of Bengal and Nepal border.

Trivia: Among several trips to Sandakphu during my tenure in WB, once I went there hiring a local Bolero. After Meghma, the driver stopped for a break and knowing about my previous self-drive to the top he obliged me to drive the Bolero. I drove it for few hundred meters from Meghma. I didn't notice or enquire about the FWH back at that time. But the steering feel was lighter than my Thar. And the driver was launching the vehicle in 4L 2nd most of the time. I hardly remember he used 1st gear any time. That's where the Di engine excels. Now the entire riddle is solved!

[dhanushs]

Originally Posted by purohitanuj

Point of the mod is beautifully written by you in this post:

https://www.team-bhp.com/forum/4x4-t...ml#post2989642 (Using 4L for Engine Braking/Torque with FWH Disengaged)

Excellent. Thanks for the post .. now you know how similar my thought process was to you when I was a noob learning and why I don’t recommend it now. More than a decade of 4 wheel driving has tought me that things like the axle work in Mahindra for abuse .. but not in Gypsys and Jimnys.

To have an example - I think there was a time 100% of RFC Gypsys ran with Mahindra axles and not Gypsy axle to accommodate for larger tyres.

Originally Posted by Samurai

I think Sutripta has summed it up perfectly in the earlier thread.

https://www.team-bhp.com/forum/4x4-t...ml#post2994995 (Using 4L for Engine Braking/Torque with FWH Disengaged)

Yeah.. like I’ve said earlier in the thread and like Sutripta has said here .. commercial vehicles / old Mahindra vehicles can easily run at 1.5t - 3t rated load. But I don’t think a vehicle like Jimny can. Hence my RFC example above.

[purohitanuj]

Originally Posted by dhanushs

Excellent. Thanks for the post .. now you know how similar my thought process was to you when I was a noob learning and why I don’t recommend it now. More than a decade of 4 wheel driving has tought me that things like the axle work in Mahindra for abuse .. but not in Gypsys and Jimnys.

To have an example - I think there was a time 100% of RFC Gypsys ran with Mahindra axles and not Gypsy axle to accommodate for larger tyres.

I get that you were not sure about how things may work or break at that time. So the purpose of this mod had been clear to you already. There are n ways to bust axle (which has been your focus) . Some other examples:

• Say someone with diff lockers tries to run his car with a load on tarmac; it will bust the axle.
  
  Putting 30" tyres can also bust the axle

When you said that commercial vehicles are designed to take a lot more stress, you meant the chassis or the drivetrain? Does a normal Bolero Pickup and a 3T Bolero Pickup use different drivetrain components?

My post is to make people aware of pros/concs of the 2WDL technique so that they dont have to learn from their own mistakes.

Just to share, the axle of Jimny are much more solid than the RWD Commercial vehicle from MSIL i.e. Eeco.

[RoadAtlas]

So can anyone please summarize?

Suppose I have a Jimny and trying to reach Sandakphu. I need to engage 4L/4H, but while moving through the sharp turns, there will be sufficient stress on the transmission as there will be significant difference between the speed of the front and rear axles.

So what is the standard operating procedure in such cases?

[Geo_Ipe]

Originally Posted by RoadAtlas

Suppose I have a Jimny and trying to reach Sandakphu. I need to engage 4L/4H, but while moving through the sharp turns, there will be sufficient stress on the transmission as there will be significant difference between the speed of the front and rear axles.

1. Try in 2H. As far as I know, 2WD vehicles also make the trail.
2. If not possible, try 4H. If you feel the load on the axles are too much while turning, you may need to do one or two 3 point turns extra.
I have assumed that the tyres are weaker than the axles here. If load gets too much, one would expect tyre slippage.
3. 4L is usually not required on paved surfaces.

This is my understanding. Please correct me if I'm wrong - always happy to learn!

[BlackBeard]

Originally Posted by purohitanuj

Some of the examples where one would want to do it:
3. Towing a vehicle on roads.
e.

Can you please elaborate on why 2WDL would be required to tow a vehicle on the road?

[murlidar]

Originally Posted by BlackBeard

Can you please elaborate on why 2WDL would be required to tow a vehicle on the road?

I think the extra load of towing a heavier loaded vehicle ( say uphill) would require extra torque which would be available in the 2WDL mode (without using the 4W DRIVE) and, that torque would not be possible to achieve on the hard tarmac. As driving on hard tarmac using 4W would damage the transmission. The idea is to achieve higher torque and power to only the rear wheels using the 4WL GEAR SHIFT lever on tarmac without sending power to the front wheels. Simply removing the fuse 24 as suggested by PurohitAnuj would achieve the above in such situations, whenever required. This hack would be impossible to achieve otherwise. Thanks to PurohitAnuj we now can drive in 4WL on tarmac without worrying about the transmission and achieve the higher torque and power to only the rear wheels.

[BlackBeard]

I don't think it is a safe/good idea to do so. Going uphill and towing a heavier vehicle while doing so in 2WD Lo will snap your rear axle. The additional torque required to do both at the same time will be immense, 4WD High should be sufficient.

[purohitanuj]

Using 4WDL without locking front hubs is quite common practice. One can see in the following youtube video (from 9:10) as well.

https://youtu.be/eVnWYLMP0io?si=p_yEKvWY1sfUEs8K&t=548

Many overlook the reduction of engine power at high altitudes, which actually makes this a very viable solution.

[purohitanuj]

Originally Posted by BlackBeard

4WD High should be sufficient.

You mean 2H right as 4High would result into 2High or do you mean regular 4High (on Tarmac Road!?)

[purohitanuj]

Originally Posted by murlidar

This hack would be impossible to achieve otherwise. Thanks to PurohitAnuj we now can drive in 4WL on tarmac without worrying about the transmission and achieve the higher torque and power to only the rear wheels.

Thanks for the response here. Even if one is towing on level surface, this 2WDL config should allow better power delivery, engine braking and a lot more control ( very slow rollover / crawl etc).

[murlidar]

Originally Posted by BlackBeard

I don't think it is a safe/good idea to do so. Going uphill and towing a heavier vehicle while doing so in 2WD Lo will snap your rear axle. The additional torque required to do both at the same time will be immense, 4WD High should be sufficient.

Snaping rear axle is a very remote possibility(engine stalling may be earlier) but one thing you are certainly assured without doubt is to snap your transmission if you drive 4WD high on tarmac as suggested by you.

[BlackBeard]

Originally Posted by purohitanuj

You mean 2H right as 4High would result into 2High or do you mean regular 4High (on Tarmac Road!?)

4H indeed, not 2H...normal 2wd drive towing is a regular activity on our roads isn't it, even cars engage in it?

Originally Posted by murlidar

Snaping rear axle is a very remote possibility(engine stalling may be earlier) but one thing you are certainly assured without doubt is to snap your transmission if you drive 4WD high on tarmac as suggested by you.

You suggested towing a heavier vehicle uphill on 2WDL is a possibility.
So 2WDL will only stall the vehicle whereas 4WDH will snap the transmission, in entirety? Speaking from experience I presume?