TRD OR Locker control.

It's my understanding that the locking rear differential is only capable of being activated in 4L. It's electric so why can't the locker be engaged independently with a separate circuit?

 

Cause Toyota needs to protect you from yourself.

My guess is someone will make a bypass. Ford E-lockers can be locked in any drive mode but they disengage above 25 mph and people make relays to bypass it so it can be activated at any speed

 

I believe in Tacoma’s and 4R’s they use a relay or other simple electric logic that only allows the circuit to be completed when in 4L. There are simple wiring mods on those vehicles that allow you to lock the differential in any transfer case mode.

With the Tundra, I’m unaware if it’s a simple analog lockout that limits the locker to 4L or if it’s more complex than that. As stated above, someone will probably figure out a bypass.

 

I've thought of this before I got my truck. I wanted the TRD OR because it has the electric locking diff. Then found out it only works in 4L. I was thinking it could be activated via a separate switch directly to the locker. Old bosses f150 was nice that you could just engage the rear locker if you was spinning in wet grass, instead of having to spend the time to get to 4L.

 

This wouldn't matter near as much if we had a clear understanding from Toyota on how the Auto LSD works in the different trims and drive modes.

 

Is the TRD OR supposed to have auto LSD as well?

 

Yes, per the window sticker and Toyota website.

 

Auto LSD is marketing lingo that makes people think it has an actual mechanical limited slip differential. It uses electronics and brake application to a spinning wheel to attempt to divert torque to the wheel with more grip. It's not a bad system, and works in slippery conditions, but it is not a true LSD.

 

Right but it's unclear it the non-TRD 4wd has Auto LSD at all, and in which drive mode is it active.

 

Increased traction in the rear.

 

Ford allows the rear e-locker to be engaged in any drive mode, but it automatically disengages at 25mph.

 

It would eat your tires up too.

 

Misunderstood physics and confirmation bias.

 

Care to elaborate a bit?

 

A true locker would eat the tires up when you turn. The old Detroit lockers were great for drag racing but made a lot of noise when you made a sharp turn. This is why Limited Slip difs became so popular. You gained some of the benefits of a full locking dif going straight but the clutch pack allowed slip around turns.

 

I know how it works, my 14' and 19' had it but you had to push a button to turn it on. My 22' doesn't have said button. I thought because it has the electric. locking diff., as to why there's no button. It works ok, but not at slow speeds. Seems like you have to have a little wheel speed for it to direct a slip and apply brakes to the spinning side.

 

While it's called "4WD" the truth is that it's only 2WD in really adverse traction conditions, just like FWD or RWD vehicles with open diffs can also become 1WD (one wheel peel). Because both axles can "one wheel peel" in low traction issues, you can still get stuck in a 4WD with open diffs.
Being able to lock the rear diff basically gives you 3WD, which can significantly improve the truck's capabilities in certain circumstances.
If you could lock just the rear, you might find you don't even need to select 4WD.

I had HLSD installed on my truck a few years ago, and it will "lock" pretty readily, I have found I rarely need 4WD anymore. And I off-road frequently, locking rear diffs are very useful.

 

What does the H stand for in HLSD and do you mind if I ask about how much it costs to add LSD to an existing open rear end?

 

Helical.

I had a TruTrac installed, cost $2300 right before the pandemic. Might be more now.

I really like the TruTrac, but when I get a Tundra, I'm going to opt for the OEM electric locker.

 

I have a Trutrac in my classic car. I like how it's there when you need it but not noticable when just driving easy. It handles the horsepower and torque seamlessly

 

@OnThaLake. Thank you for expaining. Have you researched if the OEM locker in the Tundra uses the same axle housing as the open dif? Can the locking dif be purchased as a complete assembly? I realize the axle shafts would have be pulled to install but it would be great if you could get the whole assembly. Or do you mean purchase a truck with factory installed option?

 

I don't currently own a Gen 3 Tundra.

From what I've read so far, and I hope I'm not wrong....the Tundra open diff rear end is slightly smaller than the electrically locking rear end. From what I've researched, you'd have to exchange the entire rear axle assembly on a Gen 3 Tundra, and then you'd have to figure out how to control it.
On older trucks, simply apply +12vdc will actuate the locking diff, but I hear that newer trucks aren't so simple.

That's why I will definitely be buying a truck with a locker from the factory.

 

As far as controlling the factory locker with a bypass, I'd imagine it will be a situation similar to the 3rd gen Tacoma. Is it possible? Likely. However without some trick circuitry, you will trigger a DTC.

Both lockers use the same activation principle, and the ECU measures/obtains the locker status by checking feedback from the coil which actuates the locker. If things don't check out, a DTC is triggered.

 

I'm wondering about adding locker to open dif on non TRD OR. If we had a direct power feed outside of the ECU then locker status doesn't matter because the ECU isn't looking for it on a non locker Tundra. I just wonder if they use some kind of canbus set up that requires multiple circuits to be completed before energizing the locker. I think next step is looking at the connection plug on the axle to see how many wires it has. If more than two it may get messy like the OEM light bar on the PRO. The price on the carrier sub assembly (41101-0C040 thanks Ryan) isn't bad. Not sure what comes with it though. Need to check spline count on axle shafts to make sure same for open and locker. If axles have different part numbers then might be a no go. Going to need to do some more research.

 

Here's some info.

 

Good info thanks Terry

 

High speed desert running, pulling a boat out of the water where you need traction but not all the extra torque, any application where you want both rear tires turning with high wheel speed (aka RWD donuts)

 

In regards to locking at higher speeds, I don't think I was trying to rationalize that. I agree it's not needed at higher speeds.

Some people prefer how Ford does it, available in 2WD up to a certain speed.

Some people want to turn it on anytime they feel like it.

Toyota must want people to be real sure if they need the locker, by requiring 4L Toyota must feel the locker is less likely to be used inappropriately.... like they don't trust us!

 

Since I've added TruTrac to my current truck, I no longer need 4WD to pull my boat out of the water, even if there's gravel or smegma on the ramp. It's one of the more obvious benefits of rear locker....

 

Only thing I can think of is that it is easier to shift into 4H than 4L. So, unless you really need that extra low low gearing for some specific reason maybe just using the locker in 4H would be enough 90% of the time.