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front auburn, eaton or something else?

Watch it, buddy. I WORK for Bombardier! Well, that is right now. We are cutting 20% of our work force next week. Wonder if I'll be wheelin my rig or livin in it!

Brian
A new day.... May God be with us all.
<a target="_blank" href=http://tx85gmcguy.alloffroad.com>My Tribute</a>
 
No offense, but I'm not quite sure where this explanation about a "torque sensing" versus other type of limited slip differential came from but it is not really accurate. For example, on a spring loaded clutch limited slip (aka Eaton Posi) the clutchs are applying a constant and consistent force to each other. There is nothing that changes inside the diff when one tire starts spinning that will somehow then start to limit the slip. On most limited slips (Eaton, Tru-Trac, Trac-lock, Auburn, etc...) both tires on that axle will spin up to the point in which the bias (difference between traction of the two tires) is overcome, at which point only the tire with the least amount of traction will spin. Once you have only one tire spinning you can sit and spin the tire all day long, but as long as the bias between the two tires does not change the other tire will not start spinning.

ABS based traction control systems, or the progressive "hydro-lock" axles optional in the Jeep Grand Cherokee, will behave in the manner you described....meaning that the system detects wheel slippage and then the system reacts and actually "changes" something to then limit slip.

Anyway, I have ran an Eaton Posi (carbon fiber clutches, "normal" spring preload) in my front 10-bolt for about 4-5 years now. When first installed, the truck was a daily driver and was only used to play in the mud and snow. The Eaton worked very well under these conditions, though driving on icy streets in 4wd demanded more attention. Once the truck was retired to a play vehicle and started being used on progressively harder trails, the Eaton showed it's weakness when getting really twisted up and sometimes lifting a tire as I get lift with only one tire spinning in the air.......though it is a big step up from an open diff I am planning on a locker.

I ran a Detroit Tru-Trac in the rear 10-bolt for about 4 years before swapping in a locked 14-bolt. The Tru-Trac in the rear really was not noticable, to me, on the streets and behaved very well. My opinion is that is worked a little better on the trail than the Eaton and was also more responsive in regards to lightly applying the brakes to get it to "lock up". While using the brakes got me through most trails it did make it more difficult, and once going to a true locker in the rear I did notice more of an improvement on the trail than expected. I still have the Tru-Trac in the garage and am considering installing into the front in place of the Eaton just to see what it does.
 
Once you have only one tire spinning you can sit and
spin the tire all day long, but as long as the bias between the two tires does not change the other tire will not start spinning.

I am not sure I understand the way you use the term bias in the above ! If you apply the brakes does the "bias"
change ? In a dymanic situation if one wheel spins/lifted/lesstraction, and you apply the brakes, what happens to the spining/lifted/lesstraction tire ? Answer it slows down and the applied torque increases, by design the torque
to the other tire will also increase.
 
In the words of Carroll Smith " When a torque imbalance at the tires tries to rotate the end gears at different speeds, because worm gears are capable of transmitting torque in one direction only, the frictional resistance in the worm gears resists the differential rotation. The unit thus sences the traction available at each wheel and splits the drive torque proportionally... The torsen is a torque sensing diff - it will react to unequal traction conditions and bias the input torque tward the laden wheel before the unladen wheel exceeds its lmit of traction." Carroll Smith is a race car engineer that has been around for a long time (as in GT-40)!

'71 Blazer CST w/ a 400sbc, 4" lift, 36" Supper Swampers, and alot of rust
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6.2Blazer: So was driving with the tru trac out back pretty much like driving and open diff in the snow? Or was it better? Also does it kinda do the kick out and stuff or a detriot locker in those same snowy/icy conditions? thanks

-Mikey
1987 Chevy K5 Blazer- 350 TBI
<a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>
 
I run a lock rite up front and an auburn out back. Works for me.
Shawnboy.

If you are having too much fun it's probably illegal.
 
tnn had a hummer on today with the true trac/zexel torsion type dif. good explanation of why they dont work.
after you spin out apply the brakes, slowly release the brakes and apply throttle until the vehicle begins to move, then maintain the exact same braking force until you are out of trouble or the dif goes open on you again.
no thanks. i am so glad i didnt buy that
 
That's true of any limited slip diff. The Torsen just operates much more smoothly. If you don't want to live with a locker then you have to learn how to modulate the brake pedal from time to time.
wink.gif


<font color=black>HarryH3 - '75 K5</font color=black>
<a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
It's a great day to be alive...
 
I am using the term "bias" to describe the traction difference, or more accurately the resistance to turning, between the tires on either side. Yes, applying the brakes does change the "bias" between the two tires on the axle.
I believe your question is basically, "if you apply the brakes then both tires on the axle get equal braking power, so how does that change the bias?". My guess is that it has to do with the percentage of the total force the brake exerts on that particular tire. For example, if one tire is off the ground (0% resistance to movement) and the other is firmly planted on the ground (100% resistance to movement), then a small amount of brake force will have a big impact on the tire in the air that had absolutely no resistance before where as the amount of brake force on the tire that is on the ground is very small compared to the resistance it already had just by being planted on the ground.
 
Take out the term "torsen" and you can apply that definition to just about any type of limited slip diff. However that definition is a little over-simplified. A limited slip differential can only bias the torque input to one wheel to a certain extent, meaning it will only keep both tires spinning if the traction difference between the tires does not exceed the frictional resistance of the worm gears.
Also, the phrase "thus senses the traction available at each wheel....." can also be a little misleading. The diff is not really "sensing" anything, the diff is always trying to keep both tires spinning the same speed.
 
It's not like driving an open diff on icy roads. It has the typically posi characteristics on slick roads but it's really smooth and predictable. On the other hand, the previous factory Gov-Lock (a Detroit Locker would probably be the same) caused a few intense moments as it would have the tendency to unlock and lock at, what seemed like, random times. Quite frankly, I get frustrated driving a truck with an open diff (especially pickups with no weight in the bed) as you just spin the tires all of the time when taking off, and I think posi equipped rigs are more predictable.
 
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