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Discussion Starter · #1 ·
FYI: I just stumbled on this site-
http://www.mkiv.freehosting.net/articles/torsen.htm

Torsen Differential
The strange geometry of Gleason's Impossible Differential

Constantly responding to changing road conditions, this unique differential automatically
varies the distribution of torque to a vehicle's rear wheels. Result: two-wheel-drive traction
approaching that of a four-wheel drive. It could make its Detroit debut in 1985.

As I approached the stop sign, I noticed an icy patch on the street in front of the left side of my International Scout. Several cars
had already spun their wheels on the ice, and it was polished to a slippery, glassy smoothness. I had recently installed one of the
new Torsen (torque-sensing) differentials in my four-wheel-drive Scout, and this was a perfect opportunity to test the maker's
claims. In two-wheel drive, I gently accelerated and began to turn. The left rear wheel was now on the ice, but it didn't slip. I
pushed harder on the accelerator. The rear tires grabbed, and I maintained a perfect are through the intersection as if there had
been no ice at all.

Throughout the winters of 1981 and 1982, 1 never had to use four-wheel drive. The amazing improvement in my Scout's
performance was due to the Gleason Torsen differential. This uniquely designed differential applies torque to both rear wheels
and distributes torque as required. It will deliver as much as 90 percent of the torque to one wheel, with 10 percent going to the
other.

The new differential has been proving itself in vehicles ranging from Mario Andretti's race car to the U.S. Army's Jeep
replacement. And Detroit is definitely interested. The way engine power is conveyed to the wheels by the drive train affects the
way a vehicle gets traction on a road surface. Most of us know about the first two components of the drive train: the engine and
transmission. The third part, the differential is not nearly as familiar. That part has traditionally been a major source of mysterious
traction problems for many cars.

To understand the characteristics of the Gleason differential, it is necessary first to review the "differential problem," as engineers
describe it. The problem stems from the basic nature of power-driven wheels on axles. The best way to propel a vehicle is with
power to both wheels. But in many situations, the wheels are not turning at the same speed. For example, when a car makes a left
turn, the inside (left) wheel makes a smaller are than the right wheel. The right wheel must travel farther, and the differential must
"differentiate," or compensate, between these two arcs. If both wheels were solidly driven by the drive shaft (as on some dirt-track
racing cars) and the vehicle took a sharp turn, the tires would skid, squeal, wear unevenly, and possibly throw the vehicle off a
curve at high speed.

Until now, there have been three basic ways to handle this problem. The first is the conventional differential. In normal operation
(driving in a straight line), it distributes torque equally to both wheels. But because of its internal gearing, it has a built-in preference
for the wheel with less rolling resistance (traction). This allows the wheels to make turns, but it has traction drawbacks. A
conventional differential can't tell whether you're losing traction on a slippery surface or turning. The "limited-slip" differential tries
to overcome the conventional differential's limitations. It's been offered as an option on many makes of cars for over two decades.
Through the compression of clutch packs
 

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TEG,

Thanks for the great info. I think when IS300 become more popular, it should not be hard to find a local dealership who can order the part for Torsen LSD and add on the car without LSD. Besides, the price for Tosen LSD is also justifiable from other aftermarket LSD.

Anyone knows where to buy the stock Torsen LSD or want to sell their stock Torsen LSD, please let me know: [email protected]
 

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So let's see, we've got the Rock and Roll Hall of Fame, a good baseball team, a not so good football team (nice stadiium though), and the inventor of the Torsen LSD.

Who says nothing good ever came out of Cleveland?

 

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I believe you can order a Torsen LSD directly from their website, as we did with our formula car. The one we got for our formula car costed us $330 or so, but that is because they discount to Formula SAE teams. Also, you will need to fabricate your own housing if you order from them, but if you are good or knows a machinist, this shouldn't be too difficult. And the total should be around $600 to $700 after everything is done.
BTW, I remember there is a shop in the Irvine Auto center that was selling differential for Toyota and Mitsubishi cars, so you may want to check with them to see if they have something for IS.
 

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Discussion Starter · #6 ·
I wouldn't exactly recommend replacing differential innards yourself... Do what you can to get one from the factory if you really need one. If you open the diff, and get any junk in there it can cause the gears to break and ruin the part...
 

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Actually, I just remember something. TRD usually offers LSD for all of their sport cars, and I think IS should be consider one (if they even consider the old Celica one, IS should be one). Anyway, they are usually quite fast on getting suspension kit and LSD for their sport cars, so try contact TRD regarding this and maybe get their latest catalog. I am suspecting that the half-shafts on IS300 is the same as the IS200, so you maybe able to order them directly from Japan. Check with TRD first though. Their number is (714)444-1188 and their fax is (714)444-4383
BTW, it is pretty hard to damage a Torsen diff even in its original package. The only problem we ran into with our Torsen diff on the race car is that the diff oil kept on leaking. Just for those who want to experiment with $35,000 toy, remember to have a casing that is sealed in both side and leak proof.

Daniel
 

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Bring on the snow then. If my IS goes like my SR5 4x4 did a few years back I'll be happy. It'll be funny watching my neighbor cuss his M3 (not snow friendly) if my LSD really works like this article says. Woo-Hoo.

------------------
2001 Lexus IS300
Solar Yellow Exterior
LSD, Black L/E
Moonroof, wheel locks, trunk mat
 

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Great info. If the text description still has somebody head-scratching, here is graphical representation of how the Torsen works.



It would be nice if the IS300 utilizes the T-2R, but I think it comes with the T-1, since that's what comes on the Altezza.
 
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