Detroit TruTrac Install?

Either you know less than you are posturing to know or maybe I am missing part of the equation here. The breakage BS you keep spouting seems to be exactly that.

One side is always connected and spinning with the hub and tire and that stub shaft will always turn the diff (or spiders in an open diff). Now with a CAD axle (central axle disconnect) the one stub is mechanically connected to the stub and the half shaft turns up to the disconnect. The driveshaft doesn’t turn with this setup with the disconnect unconnected and the transfer case uncoupled. Instead the spider gears spin like mad.

In a helical LSD like the Trutrac the same stuff mostly happens in the same CAD axle. The exception is the driveshaft will turn due to the planetaries in the LSD. So there is drag and fuel economy hit due to the vehicle having to turn the front DS but as far as breakage there is no binding that could cause breakage due to the CAD being disconnected in 2wd as well as the TC being disconnected. The weight and centrifugal force of the spinning DS isn’t enough to break stuff when accelerating and stopping the DS.

If I am incorrect please let me know what information is incorrect and explain the correct function of this system.

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Now the reason you want a selectable locker vs a lsd in the front is simple and is dependant on your usage on road vs off road. If you use 4wd on road in snow or other slippery conditions and have a LSD up front you tend to plow forward instead of turning. Same goes for a locked axle. Off road you are going slow in most cases that you need to be locked so it is less of a concern. With a selectable locker you engage it as needed and don’t use it full time up front. I have used a selectable locker up front in other vehicles and it is awesome. Locked when wheeling yet I could unlock it when I needed more steering in tight situations. Sometimes it just turns so much easier when the rear is pushing the front and it just freewheels the spider gears in the diff (yes I know at least one tire has driven force being plied to it). In snow a couple of feet deep I had to keep locking and unlocking to move forward AND be able to steer.

 

I'm Keen to the trutrac because it can act like a locker and still allow different wheels speeds. So on a tight spot where you want power to both wheels but also want to turn is where the torsen design is best
Also I don't want to go full locker because it relies on a subsystem for activation. Trutrac is just an all in one solution to weekend off roading. And cheaper too.

 

You're starting to sound a little lofty my friend. All the while refusing to actually contribute...

The way this diff comes from the factory you got the driver side axle always spinning the spider gears BUT HERES THE THING: I'm sure you've seen what happens if you jack up and open diff rear axle and spin one tire by hand. The opposite tire spins the other direction as long as there's no load from the drive shaft.
Now in the front of our trucks that can't be the case. Why? Because of the automatic axle disconnect (ADD) and if the stub shaft was rotating backwards (because it's connected to the passenger side spider gear and there's no drive shaft pressure in 2Hi) we wouldn't have 4wd on the fly. The passenger side tire, CV and tube axle shaft all rotate forward. Twist the knob to 4hi while driving and then if the ADD fork tried to shift the coupler over the stub shaft you'd immediately grenade parts if it was spinning backwards. Therefore there must be some type of clutch in there that keeps everything minus the ring pinion and drive shaft rotating forward so we can have 4wd in the fly.

So switch the case with the spider gears for a Torsen, what changes? The driver side CV will spin the driver side worm gear very fast. That will spin its spur gear very fast and since that is connected to the opposite side and the spur gears cannot turn the worm gear the whole thing locks together. So I guess the result could be that the Ring, Pinion and drive shaft all spin in 2Hi but since the ADD is still disconnected and the xfer case still in 2Hi there's nothing to bind

 

A helical gear LSD is not like a locker any more than a Transvestite is like a woman. A LSD like the Truetrack uses planetary gears to allow for some controlled differential between one axle shaft (side) and the other. This is different than old school POSI’s which had springs and clutch packs to limit the slip or could be overcome to make it “slip”.

The point is a selectable locker can be run like an open diff for general snowy driving conditions which involve tight turns and sweeping bends. Runs like your regular 4wd open front diff. Literally no difference. But when required you can lock and get the benefits of both wheels locked and no speed differential.

Now back to the Trutrac. There will only be “slip” if you have traction on one wheel or the other. So in slick snow where the wheels aren’t experiencing enough grip to exhibit a differential in the LSD they tend to plow just like a full locker.

I know you have made up your mind already so there isn’t a chance of changing it. But if you have never experienced what I have described I sure hope one day you don’t say hey that guy was right. Now rear end I wish we got the Trutrac in our trucks instead of the electronic locker. Now that I would be in favour of. My issue is not against the Trutrac. I think they are awesome. I almost bought one once. I am just not sold they are the right tool for the front.

 

Thanks for the info.
Although I have used torsens in full time 4wd and even in snow I've never seen them lock the two wheels together.
A torsen can never have the wheels locked 1:1 with each other, cause the point of the TBR is that even when the diff is in a 'locked' mode both wheels can still spin at different speeds.

 

It is a terminology thing. Locked is something that doesn’t apply to a LSD. When you refer to 1:1 it absolutely is possible once again they are operating at 1:1 and the word locked doesn’t apply because there can’t be locking in a LSD. That said I remember a locker that was a LSD when unlocked and then obviously had a locked feature which was a true locker.

Anyway we are splitting hairs on terminology. If you have experience and are ok with the handing of a Trutrac then go right ahead.

 

Yeah, I meant more in the manner of a 50/50 split of torque as in a locker.
I've always had good experiences with torsens. I've wheeled with other people that had lockers front and rear, and Ive had no problems following them into some sticky situations. Sometimes it helped to have a diff that can slip and still deliver power to the wheel with traction.

 

I have a Torsten up front and an AWD transfer case, so everything is spinning always. It drives just fine in all maneuvers. The only slight nuisance is that now I have some torque steer, which is mostly trying to pull the steering wheel back to center. It tracks very straight, lol.

Also, the back ordered parts to add ATRAC/VSC just shipped.

 

So you swapped in an AWD t-case? got rid of the 2wd system?

Adding ATRAC to what model tacoma? I only have a trd sport, but would love to have atrac. ATRAC plus torsen diffs sounds like a really efficient 4wd system!

 

For ATRAC to work properly you need the brake booster from the TRD off-road and you don't really need ATRAC if you have 2 torsen diffs

 

I'm not 100% how exactly atrac works, so correct me if I'm wrong, but wouldn't it remove the need to lightly apply the brakes if one wheel comes off the ground in a full torsen setup?

 

Actually, if one wheel is completely off the ground, you do need ATRAC to grab it with the brakes. I should test this for us, but I’m pretty sure that with the 3 torsens (front, middle, rear) in my truck, if one wheel comes completely off the ground I could be stuck. In the forward direction, it feels glued to the road rain or shine; will test snow soon.

My ABS isn’t working right, so I decided to try replacing it with the upgraded benefit of VSC/ATRAC. ATRAC should grab any wheel that starts to spin unlike the rest.

 

No you're right. I forgot about that tire in air scenario

 

So are you swapping in the TRD off-road brake booster?

 

I have one from an FJ Cruiser. Good luck finding one from a taco. Should also free up space for an aux battery.

 

Sweet. Post up how you're making that work with the Taco ECU and dash

 

I plan to. The biggest part is cross referencing all of the parts to see what goes where, and finding wiring diagrams for all three trucks... and studying them. It looks like most everything should work. I need to diagram the splicing first, though.

 

One wheel problem: https://www.instagram.com/p/BXyaN85BSnk/?utm_source=ig_share_sheet&igshid=daxn1ra8hg1a

https://www.instagram.com/p/BUzGLItgmtM/?utm_source=ig_share_sheet&igshid=11uxj2inin4s8