Why isn't Eaton torque biassing diff more popular

I have in front of me, "Automobile Engineering" by the American Technical Society, volume 2. It shows a torque biasing differential described as "M&S" form, and made by Browne-Lipe-Chapin. The book was first published in 1909, and this copy was printed in 1926. It is unclear what date this bit was added or whether it is part of the original 1909 text, but certainly no later than 1926.

So it is certainly not a new idea. I suspect that the main reason they have not been more widely used is twofold - they cost more than a simple differential, and most applications find this adequate, and like any limited slip or locking differential, they allow the full torque to be delivered to a single half axle, so it needs to be double the strength.

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Originally Posted by Red90

And following the trail, the first patent of the idea was 1920. US1354937A - Differential gearing
- Google Patents by John S Alcorn. Looks like Gleasman was just the first to do something with Alcorn's idea.

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So that was the Torsen Gleason diff which was an ATB???

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Originally Posted by Slunnie

So that was the Torsen Gleason diff which was an ATB???

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That's equivalent to the Torsen T1, it uses cross axis worm gears and is a torque biasing diff.
I think they were used in the Military Hummer?

The Torsen T2, TruTrac and ATB uses parallel axis helix/worm gears.

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Originally Posted by Slunnie

So that was the Torsen Gleason diff which was an ATB???

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Yes. It looks like Gleason just took the idea from Alcorn’s expired patent and developed it.

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Originally Posted by JDNSW

I have in front of me, "Automobile Engineering" by the American Technical Society, volume 2. It shows a torque biasing differential described as "M&S" form, and made by Browne-Lipe-Chapin. The book was first published in 1909, and this copy was printed in 1926. It is unclear what date this bit was added or whether it is part of the original 1909 text, but certainly no later than 1926.

So it is certainly not a new idea. I suspect that the main reason they have not been more widely used is twofold - they cost more than a simple differential, and most applications find this adequate, and like any limited slip or locking differential, they allow the full torque to be delivered to a single half axle, so it needs to be double the strength.

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It appears to be from the 1921 copy, but the differential was sold as early as 1915. But I think it might be a different principle. It is hard to find a decent picture of the internals.

Automobile Engineering

Attachment 159863

Found it. US1090082A - Differential gearing for automobiles.
- Google Patents It is the same general principle, with a different layout.

Here is a bit of a history writeup. https://www.fourwheeler.com/how-to/t...tter-than-new/

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Originally Posted by Red90

Found it. US1090082A - Differential gearing for automobiles.
- Google Patents It is the same general principle, with a different layout.

Here is a bit of a history writeup. https://www.fourwheeler.com/how-to/t...tter-than-new/

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That expands on the info I read 30 years ago on Gleasman, thanks JB.

Jim Allen the author used to wheel, fix and has a soft spot for Rovers.
Talked to him online a few times years ago.

how much more is one of these compared to a regular diff? Why was this not offered as an option?

You mean from new Bohica?

Actually the bloke who was the LR development manager who writes for LRO tested Torque biasing diffs many years ago for Defender.

There were some photos of I think the trutrack blokes and him testing them on two defenders.

Apparently it was a NIH decision by LR engineers, the same ones who would not pay for plastic sound deadening on 200Tdi.
Regards PhilipA