Is TRAC as good as a locker?

That video helps prove the point I was making. The torque required for a wheel on ice or in the air is near zero, so the same amount of torque is applied to the other wheel and you go nowhere. Brake the wheel that’s spinning and now you’re using more torque to move that wheel which means the same (more) is going to the other wheel and you can more again.

 

This is from a physics forum.

 

Good explanation

 

It doesn’t matter what terms you use to describe the phenomenon. The fact is that with an open diff, when one wheel is in the air, the other wheel does not have the power to move the vehicle.

It seems everyone has agreed on this, and now it’s just a matter of who is using the correct theory to describe why it happens.

 

He's very set on proving his point, let him be. We mistook "torque" for "power". Had you gone back and switched all our "torques" with power, we would've been right on point.

Now I'm gonna go do research on LSDs though... never even considered that as an option. Only looked at Lockers and ATRAC for my 06!

 

Only reason it wouldn't work is if it was worn out. And the additive is unnecessary.

 

Guys run spools on the street all the time. What axle did he have? No way an axle big enough for 40’s (Dana 60, 14 bolt, etc)is going to break from a spool on the street. A Dana 35 that will break on stock tires with an open carrier isn’t going to put up with 40’s.

 

Yes, of course if the wheel isn't rotating the amount of torque is just equal to the friction on the wheel and is balanced down to very little. An open diff allows the wheels to spin at different velocities, so yeah, torque isn't the right way to explain it I guess. A simple open differential takes the input speed and makes the average speed of the two outputs the same. In a partially zero traction situation that means one may be zero RPM (with traction) and the other tries to match the input (neglecting drive ratios for the sake of argument) by spinning fast against no traction.

So differentials balance the torque across the axle. Thinking of it as percentages and sending power is wrong for simple differentials (perhaps not for active torque vectoring). A differential can never send more torque than what is available, which works out to be twice the tractive force present at the wheel with the lower coefficient of friction. IOW, 100% of the engine's torque is at most split 50/50 ideally if both tires experience the exact same conditions. But in a reduced traction situation the torque split is still, just that less than 100% of the engine's torque is transferred based since less friction is present on one wheel compared to the other.

In the twisted axle scenario with a wheel in the air the amount of torque on the grounded wheel is based on the moment and inertia of the one spinning uncontrolledly fast in the air. It's not zero but it's also not enough to propel the truck forward. The differential's intrinsic characteristic is the maximum torque is a function of the minimum friction (or rotational velocity anyway).

To solve this you put torque sensing diffs, limited slip clutches, automatic lockers, manual lockers, spools, etc. in there. On the road this corrects for the weight shift as you turn, off road it prevents the wheel with no traction from balancing the differential to almost zero torque. None of them change the mechanics here. I do admit to being nonchalant and technically lazy.

 

We’re having a friendly debate, no need to bring that in here. No one was getting upset or causing trouble.

 

I may have misunderstood your post, but additive is indeed necessary for mechanical (true) LSD differentials. Many people have reported issues with using gear oils that have additive in the bottle. More additive is often needed.

 

Maybe this is a good place to mention that the LSD Differential additive was only needed for 2005-2008 SPORT TRD Tacomas because in 2009 the electronic/brake limited slip (TRAC) replaced the mechanical, 'clutch pack in pumpkin' limited slip.

 

There are good aftermarket LSD options, like Detroit Tru Trac. These options give better performance on and off road than TRAC and work fine with the stock system, from what I've read.

 

Rear differential locker won't damage anything on pavement or not except wearing tires more when turning. But if you are talking about central diff. locking then yes you can cause damage.

 

My buddy spun donuts for like 30-40 seconds on dry pavement with his locker on and he’s got 35’s.

 

This one time, at band camp...

 

Is the diff in those models the clutch pack type? I'm unfamiliar with them. If they are I'll stand by my statement.

 

The early sport models had clutch pack limited slip diffs

 

Interesting. The reason I say this is because of my experience with Fox Mustangs and the Trac-loc diff. When they wore out,or you just wanted a tighter diff, you could get an extra clutch and steel plate in there. Couple that with the heavier duty F150 spring and pow! The thing was damn near a spool. And no additive,even though the tag on the rearend cover said to use it. Someone a lot smarter than me figured out it made the diff slip more.

 

Wrong. It may not happen at once, but you are most certainly causing an exorbitant amount of wear, and the damage is imminent.