How important is the torsen front diff?

[Frank N]

All 802a 2019 and up, right? Option for 17-18 I thought.

All 802a - 2017 and up

 

[Zeusmotorworks]

Ah, roger that.

 

[pbtjrlmrt]

Need is a strong word but it's definitely preferred. It's not only for rock crawling it's also for snow, mud or any time you would normally have one wheel spinning. The torsion makes sure that both front wheels will provide traction where an open front diff will allow one wheel to spin. THe rear has a locker feature so no issue there. I say it's definitely worth it and necessary to get the most out of your truck.

 

[jzweedyk]

Do you want a 3 wheel drive truck (rear locked) or a 4 wheel drive truck (rear locked and torsion)? That is the question.

 

[Socalbeachbum]

Do you want a 3 wheel drive truck (rear locked) or a 4 wheel drive truck (rear locked and torsion)? That is the question.

Ummm ok...

 

[Jeff-Ohio]

I’m looking at getting a second 800a raptor and the only one I can find doesn’t have it. Mine doesn’t either but I wasn’t aware of the option at the time I purchased mine.

It is an option on the 800A. I had it on my 2017 and purposefully did not get it on my 2019 because I did not like the feel of it when turning the wheel. If you off-road a lot or live where there is a ton of snow, then get it. If neither of those conditions exist, the truck drives much nicer without it.

 

[OriginalToken]

Do you want a 3 wheel drive truck (rear locked) or a 4 wheel drive truck (rear locked and torsion)? That is the question.

Ummm ok...

That really is the answer and question right there. Do you want, or need, 4 wheels driving, or is 2.5 / 3 good enough?

An open front dif means that in low traction situations, whatever conditions are causing them, mud, snow, sand, etc, one of the two wheels will have more traction than the other, and the other wheel (the one without the traction) will be getting all the torque / power, wasting it. The front axle will, realistically, turn into a one wheel drive system, always transferring power to the wheel with the least traction. With the rear locker engaged this will end up being a situation where one front wheel (always the one doing you the least amount of good) and both rear wheels get power.

This makes the vehicle a 3 wheel drive, and one wheel along for the ride, situation. And the only front wheel driving is the one that is doing you the least good, making it almost a 2 and a half wheel drive.

And without a front LS, with the rear locker unlocked, and transfer case in 4WD, the vehicle can / often will revert to a 2 wheel drive configuration, one front wheel and one rear wheel, and both of them the wheel with the least amount of traction. Literally the two worst wheels for your conditions will be the two driving.

View it this way. A vehicle with 4WD selected, and configured with an open front dif, open rear dif and rear locker not turned on. You cross a small gully on an angle, with the left front tire and the right rear tire in solid contact with the ground, this means the right front / left rear are in light / no contact with the ground. Because of the open difs, all of the power / torque will go to spinning the two tires in light / no contact with the ground, not to driving the two tires in solid contact. You can literally be left hanging, unable to move, with one wheel on each axle spinning in space, while the other wheel on each axle is in solid contact with the ground but doing no work to pull you out. The same thing can happen on flat ground in low traction like snow.

When the front end has an LS of some kind, including the Torsen, then power will go to both front wheels, regardless of traction conditions. Combined with a rear locker this makes the vehicle truly 4 wheel drive, under all conditions. In the above scenario all 4 wheels will drive, regardless of traction conditions, meaning the two wheels in solid contact will pull you out.

With a rear locker present the question is less imperative, but in my opinion (and I recognize it is just opinion) all 4WD vehicles that will actually be used off road or in low traction situations should have LS in the front, so that worst case, with 4WD selected you have at least 3 wheels (two front and one rear) driving.

Yes, the TCS/Stability system will partially make up for this. Yes, the rear locker in the Raptor will partially make up for this. But having all the tools available is my preferred option.

T!

 

[BroncoAZ]

That really is the answer and question right there. Do you want, or need, 4 wheels driving, or is 2.5 / 3 good enough?

An open front dif means that in low traction situations, whatever conditions are causing them, mud, snow, sand, etc, one of the two wheels will have more traction than the other, and the other wheel (the one without the traction) will be getting all the torque / power, wasting it. The front axle will, realistically, turn into a one wheel drive system, always transferring power to the wheel with the least traction. With the rear locker engaged this will end up being a situation where one front wheel (always the one doing you the least amount of good) and both rear wheels get power.

This makes the vehicle a 3 wheel drive, and one wheel along for the ride, situation. And the only front wheel driving is the one that is doing you the least good, making it almost a 2 and a half wheel drive.

And without a front LS, with the rear locker unlocked, and transfer case in 4WD, the vehicle can / often will revert to a 2 wheel drive configuration, one front wheel and one rear wheel, and both of them the wheel with the least amount of traction. Literally the two worst wheels for your conditions will be the two driving.

View it this way. A vehicle with 4WD selected, and configured with an open front dif, open rear dif and rear locker not turned on. You cross a small gully on an angle, with the left front tire and the right rear tire in solid contact with the ground, this means the right front / left rear are in light / no contact with the ground. Because of the open difs, all of the power / torque will go to spinning the two tires in light / no contact with the ground, not to driving the two tires in solid contact. You can literally be left hanging, unable to move, with one wheel on each axle spinning in space, while the other wheel on each axle is in solid contact with the ground but doing no work to pull you out. The same thing can happen on flat ground in low traction like snow.

When the front end has an LS of some kind, including the Torsen, then power will go to both front wheels, regardless of traction conditions. Combined with a rear locker this makes the vehicle truly 4 wheel drive, under all conditions. In the above scenario all 4 wheels will drive, regardless of traction conditions, meaning the two wheels in solid contact will pull you out.

With a rear locker present the question is less imperative, but in my opinion (and I recognize it is just opinion) all 4WD vehicles that will actually be used off road or in low traction situations should have LS in the front, so that worst case, with 4WD selected you have at least 3 wheels (two front and one rear) driving.

Yes, the TCS/Stability system will partially make up for this. Yes, the rear locker in the Raptor will partially make up for this. But having all the tools available is my preferred option.

T!

I agree with you on the need for the front diff. I wanted to add that in your ditch scenario use of the parking brake or the foot brake is usually enough to get some torque transfer to the tire with traction and get you moving again.

I began my off-roading in a Bronco with two open diffs. First upgrade was to a LS rear, when I shattered that I went to a Detroit locker rear, when I broke the 8.8 I went to an 9” with ARB rear followed by the ARB front. The dual selectable lockers is the best setup I’ve used.

 

[Socalbeachbum]

You could probably add some kind of a Detroit True Trac diff to the front of you wanted to, but it’ll cost far more than the $500 it costs on a new truck. I have been crawling with a dual ARB locker equipped truck for many years and definitely wanted the Torsion diff in my Raptor. I don’t plan on rock crawling my raptor, but I like the idea of the front pulling more coming out of turns at speed on dirt roads.

I agree with GCATX that the Torsion may make things harder on slick or snow covered roads, but I’d rather have it than not have it. I do live in snow country and will find out. I’m guessing all of the electronic systems in the truck will keep it sorted out.

https://www.steeda.com/Ford-Perform...al-88-Front-Axle-F-150-2004-2017_p_14028.html

I could just have this installed right? It’s says 2017 but I’m assuming it’s the same.

 

[BroncoAZ]

https://www.steeda.com/Ford-Perform...al-88-Front-Axle-F-150-2004-2017_p_14028.html

I could just have this installed right? It’s says 2017 but I’m assuming it’s the same.

The labor would probably be another $500-800. If possible it would have been cheaper to order it with the new truck, but yes I believe that would work.