All Wheel Drive ?

[jack neville]

I wonder how many 4x4 or 6x6 vehicles produced by various countries were full time all wheel drive. Most have a transfer case to disconnect the front drive. Could this have something to do with MH AWD claim.
The later Ford Marmon Herrington gun tractors were fitted with a ‘compensator’ transfer case to eliminate windup in the driveline. A primitive centre diff.
For an Australian built vehicle to have full time AWD was quite unusual I’m thinking.

[Grant Bowker]

Going back to the M135, all of the SAE terms:
On-Demand Synchro Variable Torque Passive System
On-Demand Synchro Variable Torque Active System
On-Demand Independently Powered Variable Torque Active System
seem awfully fancy compared to a system that was of the same vintage as the early LandRover described above (only slightly fancier in being linked to the reverse shift position, the truck had an automatic transmission as well to simplify driving). The variable torque of the M135 is basically binary, either engaged or not.
It would seem that the SAE J1952 standard was first published 1991,(well after the M135 and LandRover were designed) https://www.sae.org/standards/content/j1952_199101/ and to be a bit picky is only intended to apply to light trucks up to class 3 which seems to top out at 14000 pounds GVW. https://en.wikipedia.org/wiki/Truck_classification It isn't clear if this is the same class 3 definition SAE is using.
I could facetiously claim the 4wd system on my F350 is also "on demand" - when I demand power to the front wheels by moving the floor mounted shift lever, power is delivered.

I wasn't trying to tell anyone they were wrong, only to suggest that are a large variety of systems that can't all be neatly pigeon holed.

[Lang]

Grant

I was not suggesting you are wrong just that the SAE main descriptions are general names for the only three possibilities to achieve all wheel drive. Even then one could argue "on demand" is really a part time system. How they are arrived at is only limited by the imagination of the engineers and how complicated and expensive the manufacturers are willing to pursue development of the weird and wonderful.

I think the 3 general descriptions (part time, full time and on-demand) cover everything possible but the sub-list of methods and designs to achieve one of those 3 results will go on expanding forever.

It is still hard to pigeon hole a design. What about a vehicle that normally runs 90% rear and 10% front - got to be full time. But if it has sensors that detect rear wheel slip and feeds power to the front axle until there is a 50/50 sharing it has got to be on demand? And if you can turn the four wheel drive off completely it has to be part time?

Lang

[Lang]

Mike K

Thanks for the Landrover info.

Lang

[Mike Cecil]

Just love these wandering discussions .... just like asking 'what hat do we wear on ANZAC Day?' at a VMVC meeting!

Very interesting stuff, guys. I figured the collective wisdom would provide a veritable bounty on interesting replies: thank you all.

Mike

[Ken Smith]

Don't forget International called their 4 x 4 trucks, including our own teaspoon tippers All Wheel Drive. They had a nice little badge on both mudguards/fenders.
The badge was on AA series and the AB series as far as I know, and the same badge was used on the four cylinder Scouts from the early sixties.
Ken

[Hanno Spoelstra]

A lot is written about this subject already, but I’d like to add that Marmon-Herrington’s core business, since 1931, is the design and production of All-Wheel Drive conversion kits (they built complete vehicles, even tanks, as well).

“All-Wheel Drive” was incorporated in their old logo, and the term was actively marketed by them.

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Maybe they had it trademarked or patented? That is what I would have to look into. For now, I leave you with a link to my old M-H website:

http://www.mapleleafup.nl/marmonherrington/

HTH,
Hanno


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[Lang]

Here is an interesting Quad story.

http://archive.commercialmotor.com/a...ment-for-mules