Front diff diff.

mog

Kodiak Buckaroo
Ok, so as I ever so slowly get smarter, it appears that both the Quaife and the Torsen LSD's are best suited for on road use. They do not bias enough of the torque to deal with one wheel off the ground or spinning freely to be effective. Hence the concept of having to apply the brakes to get them to function. Starting to make sense.
Both are ATB (AUTOMATIC torque biasing) diffs, so they start biasing the torque before the wheel(s) spin. Seems like the best solution, especially for a front differential.
I'm no expert but it seems the experts (ATW, EC, Alan) have gone with what they have determined is the best. I'd be happy to follow their lead.
 

GR8ADV

Explorer
Both are ATB (AUTOMATIC torque biasing) diffs, so they start biasing the torque before the wheel(s) spin. Seems like the best solution, especially for a front differential.
I'm no expert but it seems the experts (ATW, EC, Alan) have gone with what they have determined is the best. I'd be happy to follow their lead.
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Agreed, I think their solutions are indeed the best (and only) ones out there. I was just curious of the differences between them. In my research I became confused with the need to brake. I like to know how things work. It makes more sense now. And to back up the braking and lack of torque bias issue for offroad use with ATB LSD's, I found these posts from other threads. Possibly a clutch pack LSD system would work better with respect to a wheel off the ground, but I am not sure.
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I spoke to Quaife at length about my disappointment with the diffs for off road use and I sent the diffs back to them a couple of times to make sure they were within spec before getting one of their engineering types on the phone. He said that the problems I was experiencing (no difference between Quaife and an open diff off road) was to be expected because the diff simply isn't designed for off road use and they would never recommend their diffs for that purpose. The diff needs resistance from both wheels to work and as soon as one wheel loses traction all the power will be sent to that wheel..
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As others have said it will spin a single wheel with no resistance, I've propped the axle on a log to test it, I can't really explain it but you can feel it trying to 'engage' as the revs rise. If you blip the throttle it will just drive off the log so power is getting across the axle somehow. Likewise at low revs just dabbing the brakes will make it drive off the log.
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That is exactly the trick with them, TC or left foot braking, just a tiny bit makes a massive difference! and you find that the bigger the wheels / tyres you have the less you need to brake as the large mass of the big tyres will give enough resistance to make the Torsen system come into play.
 

Aussie Iron

Explorer
Ok, it appears that both the Quaife and the Torsen LSD's are best suited for on road use. They do not bias enough of the torque to deal with one wheel off the ground or spinning freely to be effective. Hence the concept of having to apply the brakes to get them to function.
Well I can tell you that I more than once had a front wheel in the air and if I had no drive to the other front wheel it would have been back down and try another line. At no time did I use brakes to to get the diff to operate, maybe throttle as it would have been on climb or through mud or sand.
 

yabanja

Explorer
The hard core rock crawlers dislike Torsen diffs.

There are some benefits to them however. They will not wear out like clutch style diffs. Also, most other types of lockers (with the exception of air lockers) are very hard to live with on the pavement-particularly in the front of the vehicle as their engagement and disengagement tends to be very harsh.

With up to 30 inches of articulation on these trucks, having a wheel leave the ground is not that common. Generally just adjusting your line slightly will correct the problem when it does happen.

Really, there is no point in having this discussion as there are no other options available! I personally long after a front diff but it is a long way down the list of priorities-(Diesel heater, solar setup, under camper storage boxes, etc....)

Incidentally, the only time I have gotten stuck thus far a locker wouldn't have helped- I was pushing so much dirt with the axles that the truck stalled in 2nd gear low range- i.e. not a traction issue. Even with 37" tires the clearance under the diffs is really not great.

The video Aussie Iron recently posted demonstrating Alan's sand ladders demonstrated the front locker quite well I thought!

Allan
 

SkiFreak

Crazy Person
Really, there is no point in having this discussion as there are no other options available!

I believe that the question was not about whether an ATB diff was the way to go, rather which one of the ATB diffs that are available is the best.
This will always be a contentious question, but I figure any of them would be better than a standard open diff.

And to be pedantic... none of these diffs are actually lockers.
 

mog

Kodiak Buckaroo
I personally look forward to installing an ATB diff when funds allow. I really like the fact that they are usable 'all' of the time when needed. Snow covered paved roads (I sure don't want a locker there), light slippage, before there are issues, etc. Having had a Unimog with a mechanical front diff locker was great when it was tough going, but it was always an engage-disengage operation because when the front diff was locked, both steering and turning went out the window.
And I defer to our Aussie companies who have the most experience. If 3 for 3 went with ATB diffs that are made in England or Taiwan over a true locker like ARB that is made in Australia, that says a lot to me
 

GR8ADV

Explorer
I personally look forward to installing an ATB diff when funds allow. I really like the fact that they are usable 'all' of the time when needed. Snow covered paved roads (I sure don't want a locker there), light slippage, before there are issues, etc. Having had a Unimog with a mechanical front diff locker was great when it was tough going, but it was always an engage-disengage operation because when the front diff was locked, both steering and turning went out the window.
And I defer to our Aussie companies who have the most experience. If 3 for 3 went with ATB diffs that are made in England or Taiwan over a true locker like ARB that is made in Australia, that says a lot to me

I could not agree more. My original question was to see if there were any functional differences in how they operated. The answer to that appears to be no. Likely the 2 manufactures have a somewhat different approach i expect. I am familiar with quaife as a manufacturer. Anyone want to weigh in on the manufacturer of the EC/Allan unit?
 

SkiFreak

Crazy Person
My original question was to see if there were any functional differences in how they operated.

As I mentioned previously, there is a bit of a technical difference with the diff that Alan supplies. It has a spring loading mechanism that I am told helps if one wheel were to lose total traction (off the ground for example).
Alan could possibly give further technical insight as to why his diff was designed as it is.

Anyone want to weigh in on the manufacturer of the EC/Allan unit?

In my opinion, only Alan should be commenting on this.
 

GR8ADV

Explorer
As I mentioned previously, there is a bit of a technical difference with the diff that Alan supplies. It has a spring loading mechanism that I am told helps if one wheel were to lose total traction (off the ground for example).
Alan could possibly give further technical insight as to why his diff was designed as it is.



In my opinion, only Alan should be commenting on this.

I did ask him. He responded that his was a Torsen "style" but not made by Torsen. I do not believe Torsen has a spring. Allan made no mention of a spring in his system, and has yet to answer my question regarding the manufacturer. I am curious for several reasons, just one of which is that some manufacturers of Torsen style systems use only 3 gears. The actual Torsen has 6 I believe. Much to learn for the curious.
 

yabanja

Explorer
Another interesting aspect of this whole thing is that apparently depending upon the cut of the gears they can have different lockup characteristics.....


Allan
 

GR8ADV

Explorer
I thought part 2 of this video was interesting as it talks about automatic braking differentials to distribute torque. Basically they apply the brake at the slipping wheel thus increasing the 'load' at this wheel and the result is increased torque to the other non slipping wheel. This is roughly the same concept/result as touching the brakes on an ATB LSD. Again part 2 of this short clip describes it better. http://youtu.be/gIGvhvOhLHU
 

yabanja

Explorer
Pretty much all modern vehicle have this system. It is called traction control. It is really just a reprogramming of the abs system. The problem is that the brakes tend to overheat in slippery conditions. Ideally a car with mechanical locking differentials and traction control will work best.

Allan
 

alan

Explorer
I did ask him. He responded that his was a Torsen "style" but not made by Torsen. I do not believe Torsen has a spring. Allan made no mention of a spring in his system, and has yet to answer my question regarding the manufacturer. I am curious for several reasons, just one of which is that some manufacturers of Torsen style systems use only 3 gears. The actual Torsen has 6 I believe. Much to learn for the curious.

If i get a chance during the week i will dismantle one of our LSD's and post the pic's
 

GR8ADV

Explorer
If i get a chance during the week i will dismantle one of our LSD's and post the pic's
wow now that's cool and over and above. Thanks Alan

Edit: I appreciated ATW for being transparent letting us know that Quaife manufactures theirs. Who manufactures the parts and builds yours? Thank you.
 
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alan

Explorer
Finally got to pull one apart today, pic's attached. there is a spring pack in the centre which applies pressure to the axle gears. I have enough trouble with people coping my products without giving away contact information. hope you understand my postion.








 

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