Torsen/TrueTrac helical limited slip differential?

[MrKnowitall]

I’m excited for this and following closely now. I’d definitely prefer a torsen for the rear axle even if just for better control on icey roads, but the front axle is less clear. Does anyone have advice looking at torsen/open/selectable locker for the front axle.

JL/JTs have a front axle disconnect (unlike the TJ and JK). To run a helical LSD, you need to defeat that somehow. I've had one in a TJ, and it was awesome. In 2wd, it's totally transparent. In 4wd, its fine, unless you really lean on it.

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[kd1yt]

I’m excited for this and following closely now. I’d definitely prefer a torsen for the rear axle even if just for better control on icey roads, but the front axle is less clear. Does anyone have advice looking at torsen/open/selectable locker for the front axle.

The Torsen design can do a ratio of something like 3:1 torque bias (may vary a bit above or below that with application and other things) in favor of the wheel with more traction, which is phenomenal compared to a standard open diff or a friction-clutch traditional "limited slip." But the Torsen still falls down in a situation in which you have a wheel, on one side of one axle, in the air. That's territory, if that is what you anticipate, where a locker will be the unbeatable option.

 

[RodRecket]

The Torsen design can do a ratio of something like 3:1 torque bias (may vary a bit above or below that with application and other things) in favor of the wheel with more traction, which is phenomenal compared to a standard open diff or a friction-clutch traditional "limited slip." But the Torsen still falls down in a situation in which you have a wheel, on one side of one axle, in the air. That's territory, if that is what you anticipate, where a locker will be the unbeatable option.

While I agree you can't beat a locker in that scenario can't you drag the brakes to start loading the wheel down side and getting both to turn?

 

[kd1yt]

JL/JTs have a front axle disconnect (unlike the TJ and JK). To run a helical LSD, you need to defeat that somehow. I've had one in a TJ, and it was awesome. In 2wd, it's totally transparent. In 4wd, its fine, unless you really lean on it.

I'd think you could put a helical in the front diff, even with the FAD, as long as you recognize, same as with a stock open differential, that the front axle will be doing nothing until you engage 4wd and the transfer case and FAD actually connect up the power to the front system. With SelectTrac presumably full-time 4wd would do the same.

Or is there something that I am not thinking of about the helical diff. which will invite bad results with engaging and disengaging the FAD?

 

[kd1yt]

While I agree you can't beat a locker in that scenario can't you drag the brakes to start loading the wheel down side and getting both to turn?

Possibly, but those with more experience in actually doing that and seeing how it works would need to weigh in on real world experience. And this assumes an auto transmission where you have enough feet to go around to be doing that.

 

[CerOf]

I ran truettacs in my ZJ, front and rear. In snow and ice, it could get scary.

Anything other than a nice super easy/slow start would end up in crab walking.

Once you learned how it drove, it was super fun.

Yeah, it was a V8, but todays 3.6 puts down more hp/tq.

If imhad a JT with open diffs and was set on a lsd, I’d put it in the rear only. If I wanted something up front, I’d go selectable locker.

 

[CrazyCooter]

I'd think you could put a helical in the front diff, even with the FAD, as long as you recognize, same as with a stock open differential, that the front axle will be doing nothing until you engage 4wd and the transfer case and FAD actually connect up the power to the front system. With SelectTrac presumably full-time 4wd would do the same.

Or is there something that I am not thinking of about the helical diff. which will invite bad results with engaging and disengaging the FAD?

You could absolutely put a helical posi in the front axle with some possible side effects...... We don't know if this will be a preloaded design of not.... With a preloaded design, the front differential and driveline will spin as if the wasn't a FAD. Even IF it is not preloaded, I suspect the drag from the left axle being connected would spin the differential at partial speed or maybe it could even generate enough friction to transfer the 2.75:1 to spin the differential?

Then there's the push factor in 4wd with any traction device in the front axle. I did it for years in my YJ back when I couldn't afford buy a selectable locker. Now having an e-locker in the front, I would never want to go back. Steering is SO much nicer now!

 

[CrazyCooter]

I ran truettacs in my ZJ, front and rear. In snow and ice, it could get scary.

Anything other than a nice super easy/slow start would end up in crab walking.

Once you learned how it drove, it was super fun.

Yeah, it was a V8, but todays 3.6 puts down more hp/tq.

If imhad a JT with open diffs and was set on a lsd, I’d put it in the rear only. If I wanted something up front, I’d go selectable locker.

Yes, you know exactly the situation......... They are totally torque dependent! Drive like a jackass, and it will bite you.

 

[mrmo]

Trac Lock Dana-Spicer

 

[CrazyCooter]

Trac Lock Dana-Spicer

Hard pass......better than nothing, but those are short lived.

 

[mrmo]

For real? Ive used Spicer driveline parts in hi-performance applications for years w no issues. I prefer the Auburn limited slip myself. Got one in a 9" w 4.30 gear set, 600hp w slicks, inspections once a year, no indicated wear, and i do not baby this vehicle.
Is a newer Dana 44 just like the ones from the late 70's? I built up the front 44 in my 79 Bronco, w 38's and a big block. Never one issue and i run it hard too.

 

[Wheelin98TJ]

For real? Ive used Spicer driveline parts in hi-performance applications for years w no issues. I prefer the Auburn limited slip myself. Got one in a 9" w 4.30 gear set, 600hp w slicks, inspections once a year, no indicated wear, and i do not baby this vehicle.
Is a newer Dana 44 just like the ones from the late 70's? I built up the front 44 in my 79 Bronco, w 38's and a big block. Never one issue and i run it hard too.

Dana Trac Lok is a hard pass for me too.

It's not a good performing limited slip. And having clutches means it will need a rebuild.

 

[MrKnowitall]

I'd think you could put a helical in the front diff, even with the FAD, as long as you recognize, same as with a stock open differential, that the front axle will be doing nothing until you engage 4wd and the transfer case and FAD actually connect up the power to the front system. With SelectTrac presumably full-time 4wd would do the same.

Or is there something that I am not thinking of about the helical diff. which will invite bad results with engaging and disengaging the FAD?

IIRC, the Truetrac isn't rated for CAD operation, unlike a selectable locker. with CAD, one side is usually spinning forward, while the other side spins backwards- at 8-900rpm on the highway (depending on tire size). With the CAD defeated/engaged, both are spinning in the direction of travel with minimal differential speed.
If there's a part number for a M210 front axle application, there should be an installation note about what may or may not need to be done with the CAD for highway use. The JL/JT version of the programmer I have will let you select how the CAD operates, so it can be as simple as setting it to stay engaged.

 

[Jack'D]

Showing up for all 3 years now..
Still a ghost product? Or has someone here pulled the trigger?
https://www.eaton.com/us/en-us/skuP...BHGHUqeCiuBSZcYz8cAuu1GSGpH1dGCuBYztFPz8a7PZ8

 

[JTBurns]

Man, I hope it's real!

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