Newer tacos and limited slip diffs
 

I was at the dealer the other day and saw one of the new tacos that had the TRD package on it. The sales guy said they have traction control as an option. I'm curious if you could add a limited slip like a torsen (TruTrak) to one of these or is it a waste of time? I'm thinking the traction control might not get along with a full locker like a Detroit.

My 08 Tundra has Traction Control and a rear Limited Slip Differential stock.

:wabbit2:

Toyota discontinued offering the limited slip on the Tacoma in 2008, and replaced it with the traction control system your talking about. It uses the brakes to control wheel slip, just like any traction control system.

As far as adding a limited slip to one of these Tacomas, I don't believe that it would cause any issues as far as the traction control system is concerned, but if you would like to, I would recommend looking into it a little deeper.

What kind of driving will the truck be used for?

Adding a limited slip differential of any kind to a vehicle with a traction control system that uses the brakes to slow the spinning wheel makes the traction control system that much more effective. The action of the limited slip is greatly assisted by the brakes, and the limited slip reduces how much the brakes need to be applied, reducing the overheating that reduces brake effectiveness.

So that would be a good thing.

I've used brakes with ABS as traction control. If you are spinning one front and rear wheel, applying the brakes will fool the ABS into thinking the wheels not spinning are locked, which will apply the brakes only on the spinning wheels, which will transfer torque to the wheels that are not spinning.

But, in some cases brake based traction control may not work well. It often doesn't work soon enough, allowing too much wheelspin before it works. This can make it hard to do things like rock crawl, where finesse is needed. When the traction control does finally apply the brake to the spinning wheel, the truck can shoot forward, moving it too fast and too far and causing an accident or damage. It also won't work as well when the brakes are wet or overheated.

As far as traction control not getting along with a Detroit Locker, that won't be the case. My educated guess is that the computer simply won't see the need to use traction control, since neither wheel will spin faster than the ring gear. So a Detroit makes traction control a moot point, since it effectively disables the traction control.

For the driving that I do, If the traction control is offered on a TRD with the rear locker (I don't think it is), I would keep the locker for such situations where traction control isn't as effective. If traction control isn't offered on the TRD, I would get the TRD with the locker and forget about traction control. Another option if traction control isn't offered with the locker is to get traction control for situations (ice on the road, for instance) where it will help, then get a selectable locker for when traction control isn't enough.

The simulated locker using the wheel braking looks like it might work great with a Torsen-style limited slip as near as I can tell. (Torsens shift torque from one side to the other by braking the loose wheel. But unlike open diffs, the amount of torque shifted over is multiplied.) I noticed that the TRD package has an e-locker. I would be tempted to go with the Torsen rather than the e-locker since they are very reliable.

I currently have a 1st gen 4R with a Detroit in the back and a TruTrak up front. The combo works great so long as you're not trying to do rock crawling. But the rear locker does chirp the tires when turning tight corners. I love my 4R, but I'm sorta toying with the idea of getting something with a bit more power.

(i think) my new 2011 tacoma trd sport came with both traction control and posi
and i thought the trd off-road package came with traction control and a selectable
and the traction control can be disabled
i dont know that much about it, because the truck is still new to us and i dont drive it, so i dont care enough to find out, right now

From my experience with the factory Toyota locker as well as what I've found online, the factory Toyota locker is quite reliable. I've even accidentally locked mine with one wheel spinning with no problems yet.

Gear driven limited slips like the Torsen and Truetrac do tend to be weak. I do know at one time they were only warranted for up to 33" tires. The Truetrac has supposedly been improved with an extra spider gear (3 instead of 2), but it still wouldn't be as strong as the Toyota locker.

Even the military Hummer (H1) had trouble with Torsen differential breakage. And this is despite the fact that they have portal gear reduction boxes at the wheels (after the differential), which takes some stress off the differential.

Military Hummer drivers were trained to use the brakes to cause the differentials to transfer torque to the wheel with traction. But this method was causing the Torsen differentials to break, especially if the driver hit the brakes suddenly and hard. So they had to retrain the drivers to gradually apply the brakes.

A selectable locker obviously doesn't have this problem, which is one reason why I recommend it, especially if the truck already comes with it.

why doesnt the traction control work in 4wd