[directinjection]

Originally Posted by ram

Yes the MM-440 and MM-540 were introduced in 1985. They were based on the 1955 to 1971 Willys CJ-5, with the wheelbase stretched to 93.5 inches.

The MM-440 used the one and only petrol engine Mahindra had.
The old 2195 cc "Hurricane" F4-134.

The Hurricane had an "F" head with side intake valves and overhead exhaust valves. It developed 72 bhp @ 4400 rpm and 154 Newton-metre @ 2000 rpm.

The MM-540 used the 2112 cc Peugeot XDP4.90 diesel from the Peugeot 504 cars.
It developed 62 bhp @ 4500 rpm and 122 Newton-metre @ 2000 rpm.


The CJ stands for Civilian Jeep. The term came from Willys-Overland.
They made the Willys CJ-2A from 1945 to 1949, the CJ-3A from 1948 to 1954, and the CJ-3B from 1953-1964.

The Mahindra CJ Jeeps have the following ancestry.
CJ-3B was the unmodified 1953-1964 Willys CJ-3B with its legendary 80-inch wheelbase.
In 1967, Mahindra stretched the CJ-3Bs wheelbase to 101 inches to produce their CJ-4A.
In 1975 an International Harvester MD-2350 diesel transformed the CJ-4A into the Mahindra CJ-500D.

The Mahindra CJ-340 Classic is the 1953-1964 CJ-3B with the Peugeot XDP4.90 diesel and a Korean Kia 4-speed gearbox.

You seem to have done a PhD on Jeeps.

[Ram]

Originally Posted by ex670c

By any definition SOTF has nothing to do with the ability to lock/unlock the front hub.

SOTF- implies the ability to shift in and out of 4WD while the vehicle is moving (at speeds below 45Kmph).

What stops a transfer case from being shift-on-the-fly?
It's the mismatch of speeds between the front axle and the rear axle.

Let me explain.
Do you agree that a two wheeler doing a "U" turn has a front wheel going faster than the rear wheel?

For the same reason "GEOMETRY", the front axle needs to go faster than the rear axle in a front-wheel steered vehicle, while it is taking a turn.

This causes a mismatch of speeds between the front axle and the rear axle. This is transmission wind-up. Don't try it or you'll have your front drive shaft twisted into a pretzel.

Originally Posted by ex670c

The Low Ratio must be engaged while the vehicle is stationary.

We aren't even discussing two-speed nature of the Spicer-18 transfer case.

Originally Posted by ex670c

"Transmission Wind-up is caused by a Gearbox-Transfer Case setup which doesnot have a central differential"

You're right there! The central differential is there to bleed away the transmission windup caused by steering the vehicle on an unyielding surface.

Originally Posted by ex670c

That is why it is advisable to engage and disengage while the vehicle is rolling."

Engaging the front axle drive will not prevent transmission wind up.
Once the transmission is wound up, you will not be able to disengage front axle drive, unless you reverse the vehicle and unwind the transmission.

Originally Posted by ex670c

Just because the feature has transmission windup doesnot mean its not SOTF. Don't confuse the two.

I'm a qualified engineer who has done the Rubicon in California on real Jeeps, (not Mahindras) back in the late 1980s.


I know what shift-on-the-fly means and have helped repair shift-on-the-fly mechanisms.

In shift-on-the-fly four-wheel-drive applications, you need a component called a synchro.
The synchro matches the speed of the front output shaft to the speed of the transfer case drive. It needs to spin the front driveshaft up to road speed before the front drive axle is meshed in.

Of course in a primitive Mahindra, the front driveshaft spins all the time – the front wheels are never free of the front differential.

[directinjection]

Originally Posted by ram

GTO, the Mahindra CJ-340 Classic is the 1953-1964 CJ-3B that Mahindra retrofitted with the Peugeot XDP4.90 diesel and the Korean Kia 4-speed gearbox. It is recognized as a modern-day antique by Derek Redmond and the four-wheeling community in the developed world.

Most Classics sold didn't have the lockable hubs. Mahindra didn't then and still don't make them.

Since Mahindra didn't touch the WW-II front hub design, aftermarket freewheeling hubs for the 1953-1964 Willys CJ-3B and 1955-1971 Willys CJ-5 10-spline front driveshaft would fit straight away. It's possible either Mahindra or the dealer imported and resold them on your vehicle as a one-off.

Just as Jeep wrote the book on four-wheel-drive, Warn Industries wrote the book on locking hubs. They were founded in Seattle in 1948 by Arthur Warn to produce locking hubs for surplus World War II Jeeps.

I had Warn premium (chrome & brass) manual free-wheeling hubs on my 1988 Mahindra MM 540 4x4. It took some research to find the right model.

Post 1970, Jeep had higher torque straight-sixes and V-8s in the CJ-5. The front driveshaft had 27-splines and used a different Warn model 9062.

I purchased my 10-spline Warn 29062 from a speedshop near my home in Kingston, NY. Had to instruct the shop (1971 and prior model CJ Universals).

Brought it back with me for the 540 in Bombay. Fit perfectly on the ancient design!

After the 1973 oil crisis, Mahindra had introduced a new system in their CJ series jeeps whereby the front wheel hubs could be unlocked when 4X4 mode wasn't required for a prolonged period. This was done to increase fuel efficiency while in 4X2 mode. I remember reading Mahindra's ads in Reader's Digest on this feature. Perhaps you can throw more light on this?

[ex670c]

What you have mentioned is absolutely correct, but transmission windup doesnot disqualify the SOTF feature, makes is more difficult to use.

The synchro is not mandatory in a SOTF mechanism. The real cause for
transmission windup is the lack of differential action in the G-Box-Tcase.

The Dana/Spicer 18 T-case is recognised as a SOTF capable world over.

The free-wheeling hubs fitted on M&M Vehicles are made by LAMBDA in Bangalore.
These hubs are of 2 types
1) Permanent - Semi-Conical in shape with roller bearings
2) Selectable - Cylindrical ,Lock & Free Mechanism

You did the Rubicon Valley.........................................CJ7 I presume

[Klaus17]

The legend doesnot even look like the military one that Mahndra's make. You can often spot the military version doing test runs on the Mumbai-Ahmedabad highway. They seem quite different (in terms of indicator lamps, height, tail lamps etc.)
I see them very often (obviously in their olive green paints) however last week i spotted atleast a dozen or so of them in white paint. Maybe Mahindra plans to launch a civilian version which might not be in limited numbers. And this one did seem to be a perfect copy of the military one.

Also i wonder why we dont have a civilian version of the jonga?

[Steeroid]

Originally Posted by Klaus17

Also i wonder why we dont have a civilian version of the jonga?

There is. YOu have to place orders with the VFJ (Vehicle Factory Jabalpur). Would you seriously want to buy a 1950s Toyota with a 1990 Hino truck diesel, though?

[Ram]

Originally Posted by ex670c

What you have mentioned is absolutely correct, but transmission windup does not disqualify the SOTF feature, makes is more difficult to use.

One last time, let me try to explain this more clearly:

First think about this question:

What makes shift-on-the-fly possible or impossible in a modern transfer case or gearbox? What makes any gear-shifting possible or impossible?

The answer is “Shaft Synchronization”

What impedes synchronizing your front propeller shaft with your transfer case?

In two-wheel-drive mode in a modern part-time 4x4 with freewheeling front wheels, the front propeller shaft is stationary, while the transfer case is turning.

The front wheels are spinning freely, leaving the rest of the system upto the transfer case, stationary – not consuming fuel, nor wear-and-tear.

The front wheels have manually or automatically lockable hubs, or automatically lockable half-shafts. They are in the freed state.

To shift into four wheel drive, the system must

• engage and spin up the half-shafts, front differential and propeller shaft
• wait for the system to match the speed of the transfer case
• engage the transfer case dog-clutch, so that power is transmitted to the front-differential.

Any and every manual transfer case becomes “shift on the fly” if, you fortuitously, have your front prop shaft turning, because the front hubs are

• either permanently bolted to a steel flange as in the Mahindra,
• or with locking hubs, manually locked by you.

For people with Jeeps with free-wheeling automatic hubs, pneumatic and electronic shift-on-the-fly mechanisms come with pros and cons.

Pros: You don’t have to get out in the mud and muck to lock your hubs. The integrated "shift-on-the-fly" system does that for you. While the hubs are free, you have better fuel economy and reduced front axle wear-n-tear.

Cons: They need special maintenance. After some age they are fraught with vacuum leaks or stubborn solenoids.

Originally Posted by ex670c

The synchro is not mandatory in a SOTF mechanism.

This is a completely contrary opinion to what the world of Jeeping thinks!

Originally Posted by ex670c

The real cause for transmission windup is the lack of differential action in the G-Box-Tcase.

The native geometry of front-wheel steering causes a difference in speeds between the rear differential crown gear and the front differential crown gear.

When driving on unyielding terrain such as a hard or rocky surface, the driveline cannot reconcile these speed differences.

If a single wheel could lose traction and spin momentarily the torque-buildup would be defused.

This, IMHO, defines the "transmission windup" phenomenon.
I will explain with a diagram if Team-BHPians would like that!

That being said, even an open differential will not solve the problem of optimum torque distribution.

The Range Rover solves the problem of distributing torque without transmission windup with a viscous limited-slip center differential.
Expensive Toyota/Lexus 4x4s use a torque-sensing "Torsen" limited-slip center differential. Some other high-end 4x4s use a driver-lockable center differentials.

Originally Posted by ex670c

The Dana/Spicer 18 T-case is recognised as a SOTF capable world over.

We disagree! This is just as a play with words, for the reason mentioned above, but ignorances the value of a true SOTF mechanism.

The Spicer-18 is a prehistoric transfer case, that comes from before the times of locking hubs, leave alone automatically locking hubs.

Because your hubs are permanently synchronized -- permanently locked with six bolts per hub, your Spicer-18 transfer case can be shifted-on-the-fly.
But please understand, that it has no SOTF synchronizer so, it will not

• engage and spin up the half-shafts, front differential and propeller shaft
• wait for the system to match the speed of the transfer case

In most Mahindras, the half-shafts are permanently engaged.
In GTO's Mahindra Classic, he must stop the Jeep and manually lock the hubs.

The fuel-wasting two wheel drive of the 4x4 Mahindra with bolted hubs, turns the half shafts, the crown and its planetary cage and the pinion and the front propeller shaft all the time. Not to mention the avoidable wear-and-tear on the front drive shaft “U” joints and the front differential. You lose the fuel economy and reduced wear-and-tear in two-wheel-drive possible with a true SOTF with autolocking hubs. You are deprived of the benefit of true two-wheel-drive.

Calling a Spicer-18, an SOTF mechanism is like saying a cheap fixed focus camera performs like an autofocus, because the subject is luckily at infinity.

Or like saying a stopped clock shows the correct time once in every twelve hours.

[GTO]

Most Classics sold didn't have the lockable hubs. Mahindra didn't then and still don't make them.

The CJ340 did not. But every Mahindra Classic I have seen (atleast 50 of them including mine) have had the free wheeling hubs as standard fitment. In fact, Mahindras physical sales brochure and online link also shows free wheeling hubs as standard.

The adapted Dana-18 was either 2stick or Single Stick T-case, but either ways they retain the SOTF feature.

I dont know about you, but SOTF to me means being able to shift to 4x4 even at 15 km/h. With the lack of synchronisation (As Ram rightly pointed out), it is impossible to do it while the Jeep is moving unless you want to hear the "crunch" of the moving transmission parts. The SOTF in the Armada Grand and Safari allows a smooth 4x4 shift even at 20 km/h.

GTO

[S@~+#0$#]

Originally Posted by man23ish

I couldn't stop myself from comparing the jeep wrangler and the Mahindra Legend from the pics that RAM has posted.

Somehow i feel that the jeep wrangler looks much better than our Mahindra CJ models. Have to compare them side-by-side to get the actual differences, but IMO here are the differences between them that stand-out..

1> The front grille, the wrangler's grill has more thicker bars than the MM's bars.

2> Colors, wrangler is available in far better colors.

3> Better Door-Frames and Thicker Bull-Bars on the Top.

4> A large size front Bumper giving it a Butch look..

5> The front-chrome/steel bull-bar on an MM doesn't look good at all..

So close yet Soooooooo far. The overall shape of the legend is not too different from the Wrangler still the Jeep is a winner by miles and has the sporty, fun and adventure look. The closest mahindra got to good looks was with the Classic and the Bolero(Scorpio is good but could have been much better.....new Scorpio included) but somehow they failed to capitalise. They have a long way to go in terms of build quality and engine performance.

Also, IMHO the 4 additional lights on the roll-bar and 2 on the front bumper are an overkill. A pair of Hella Rallye 3000 or a pair of KC Daylighters should suffice and look very good.

[Boom Shiva]

Originally Posted by Steeroid

There is. YOu have to place orders with the VFJ (Vehicle Factory Jabalpur). Would you seriously want to buy a 1950s Toyota with a 1990 Hino truck diesel, though?

You know, living and driving in Mumbai, I sometimes think the Jonga is the best vehicle with which to get yourself out of a traffic jam!

[apachelongbow]

Originally Posted by frankmehta

hell what a waste........
i hate this idiotic startegy of giving substandard engines at this price......who would buy one over a scorpio....

Perfectly right. Atleast Mahindra cud do is follow Tata motors way wrt to the 4x4 pickup. Atleast at a price point, Tatas have given some creature comforts like PS/AC etc. Mahindra is deluded to believe a jeep fanatic wud plonk his/her hard earned 6lacs on a chassis with a tractor engine and 2 seats. I mean i can buy a reconditioned jeep from places like mayapuri (delhi) for 50k!!!!. And to top it all puting the head honcho's signature and a green paint job, making 60 peices and calling it a exclusive range. PAH

Ravi

[Roshun]

Originally Posted by ram

In two-wheel-drive mode in a modern part-time 4x4 with freewheeling front wheels, the front propeller shaft is stationary, while the transfer case is turning.

The front wheels are spinning freely, leaving the rest of the system upto the transfer case, stationary – not consuming fuel, nor wear-and-tear.

The front wheels have manually or automatically lockable hubs, or automatically lockable half-shafts. They are in the freed state.

Ram, can you point out if Mahindra's "shift-on-the-fly" Borg-Warner electronic 4x4 system - used in the Bolero and Scorpio, is different from the one they used on the MM540? In this system too is the front prop shaft and diff still spinning in 2WD mode or have they solved that problem (and hence no need for front-axle free-wheeling hubs)?

I have driven an MM540 and a gypsy (1-litre version) extensively offroad. Whenever, I encountered "transmission wind-up" - or in layman terms if the darn thing wouldn't get out of 4H or 4L mode - I just had to reverse 10-15 feet, stop... and click... it would be as smooth as butter.

[Torque-ative]

Ram,
Considering your indepth technical know how on 4x4's, how would you classify the technology employed by Suzuki. Is it at par with what you would expect from a competant 4x4. I am an absolute newbie when it comes to 4 wheel drives, and would be great to know how the gypsy stacks up technically.

Cheers

[1100D]

Originally Posted by ram

To shift into four wheel drive, the system must

• engage and spin up the half-shafts, front differential and propeller shaft
• wait for the system to match the speed of the transfer case
• engage the transfer case dog-clutch, so that power is transmitted to the front-differential.

What about the Borg & Warner SOTF on Safari/Scorpio. Does it synchhronise the front Propeller then the front differential and ultimately lock the front hubs all by itself?

[4x4addict]

Is it possible to fit free-wheeling hubs on the MM550? Does anyone have the contact number for LAMBDA in Bangalore who make free-wheeling hubs for M&M Vehicles.

What is the spline count of the Dana 44 axles. I wanted to order diff lockers and the shop needs the spline count of the Dana 44.