Okay to engage locker if straight?

[jblc]

Is it okay to briefly (~10 meters ) engage the locking rear diff on concrete, if driving straight?

Of course, tires/etc are differently inflated, so diameters are different -- so even straight driving causes two wheels to rotate differently. But at what point does this cause damage? Is it at the level of tire inflation differences, or while turning?

I'm asking to understand the limitations of what can cause damage; I'm not planning to drive on concrete in general

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[Radioman]

Is it okay to briefly (~10 meters ) engage the locking rear diff on concrete, if driving straight?

Of course, tires/etc are differently inflated, so diameters are different -- so even straight driving causes two wheels to rotate differently. But at what point does this cause damage? Is it at the level of tire inflation differences, or while turning?

I'm asking to understand the limitations of what can cause damage; I'm not planning to drive on concrete in general

I would think traveling 10 meters occasionally would not cause a problem.

As you know, when the axle is locked, if there is no opportunity for a least one of the wheels to slip a bit, a bind is placed on the running gear because straight is not always straight and wheel diameter is probably not exactly the same. Worst case is while turning as both wheels are locked and one must travel more than the other, again no slip creates a bind. Your question at what point damage will occur is not answerable. When the bind causes more stress than the gear can handle, something has to give. Considering how easy it is to lock or unlock, I recommend not driving on surfaces that don't allow wheel slipage for any distances with the axle locked.

 

[fusseli]

That would not cause damage. You could probably do straight line burnouts if you wanted. Turning is what binds the left/right axles with a locker.

 

[Colo_Ranger]

When the locker is engaged, you're more likely to have one tire spin (lost traction) than to damage parts on your truck. I still wouldn't do it.

Anecdotal story; I had a 1985 4runner with 33" tires and a spool (read: locker that can't unlock) in the rear. When the tires were inflated to street pressures, I'd get a little bit of chirping around corners. Once, while out wheeling, I had the pressure set down to 8 psi (yup, 8) and had to go in to town for groceries. I made a hard left turn in the parking lot. Since the tires had so much traction, they loaded up real good and cause the rear end to physically jump. The group I was with said it was fun to watch, and the other grocery store patrons stared at me...

 

[Frenchy]

That would not cause damage. You could probably do straight line burnouts if you wanted. Turning is what binds the left/right axles with a locker.

Bad idea to do the burnouts as the locker will grenade from it!! This has been proven on the E-lockers!!

 

[fusseli]

Bad idea to do the burnouts as the locker will grenade from it!! This has been proven on the E-lockers!!

I wouldn't do it just saying that's where the mechanical strength is designed to be. Driving locker on pavement is about as dumb as driving 4 low on pavement but technically yes you can... straight line.

 

[jblc]

I wouldn't do it just saying that's where the mechanical strength is designed to be. Driving locker on pavement is about as dumb as driving 4 low on pavement but technically yes you can... straight line.

I think this gets to the heart of the question I'm wondering: why exactly is it a bad idea? With 4 low, based on what I've read it may be more risky (due to slight driveshaft/gearing differences between front and rear axles and the transfer case), but the rear axle is driven by the same axle.

So, what precisely makes driving in a straight line a bad idea, for a rear e-locker? (As opposed to 4 low, which I agree is bad even in a straight line)

Is it tire pressure differences (as mentioned in the original post), or is there something else to be concerned about?

Again, I'm asking mainly to understand what exactly we're protecting against

 

[JTDay]

Bad idea to do the burnouts as the locker will grenade from it!! This has been proven on the E-lockers!!

Is there something inherent about elockers that causes this? I've gone thru full sets of tires on other cars, one with a homemade spool and another with a clutch type LSD, and have never broken anything.

 

[Frenchy]

Is there something inherent about elockers that causes this? I've gone thru full sets of tires on other cars, one with a homemade spool and another with a clutch type LSD, and have never broken anything.

If you try to do a burnout with the locker engaged it will simply grenade itself. Why? Simply for the fact it is designed to help get you unstuck and not do burnouts. In a way that are strong but at the same time they are weak. Everything has its place.

 

[DHH]

I think this gets to the heart of the question I'm wondering: why exactly is it a bad idea?

It's not. Yes if you do burnouts and/or turn, it will add a lot of stress, but if you're gentle, no damage will be done.
I lock my axle almost daily in order to get up the concrete driveway at the side of my home.
Without it locked, the required articulation at the entrance causes one wheel to become too "light" and I spin.

 

[Blue Streak]

Why do locked rear ends not grenade at the drag strip?

 

[RangerDangerStranger]

I think this gets to the heart of the question I'm wondering: why exactly is it a bad idea? With 4 low, based on what I've read it may be more risky (due to slight driveshaft/gearing differences between front and rear axles and the transfer case), but the rear axle is driven by the same axle.

So, what precisely makes driving in a straight line a bad idea, for a rear e-locker? (As opposed to 4 low, which I agree is bad even in a straight line)

Is it tire pressure differences (as mentioned in the original post), or is there something else to be concerned about?

Again, I'm asking mainly to understand what exactly we're protecting against

Loading. Cross loading the differential. Those gears definition of 'straight' is sitting on a table and turing exactly at the same rate. exactly. Your truck driving 'straight' down a road is Not mechanical table straight, so your still going to cross load the diff. The amount of loading you're gonna do no one can say, it's Unpredictable. But the further you drive the greater the variance the greater of the loading. Eventually the stress Hass to be released, usually a tire will spin sometimes a gear will fail. You could probably get away with it for a while until you for the fatigue the gears enough.

 

[Dr. Zaius]

Doesn't the locker automatically unlock at 20mph?

Even doing a burnout I would think the rear would exceed that speed.

We need @Doc to comment as he drag races his truck frequently and probably spends more quality time with his locker than we do with our girlfriends.

 

[Doc]

Doesn't the locker automatically unlock at 20mph?

Even doing a burnout I would think the rear would exceed that speed.

We need @Doc to comment as he drag races his truck frequently and probably spends more quality time with his locker than we do with our girlfriends.

Drag Racing XL, 2wd, I launch at 2500, 3000 depending on boost, ASS off, Traction Control off, Locker on…Quarter Mile no binding or problems, lights both rear tires, locker light comes back at 20 -25 mph at the turnoff…
So far no problems at over 100 runs..
Regards
Doc

 

[D Fresh]

Bad idea to do the burnouts as the locker will grenade from it!! This has been proven on the E-lockers!!

Seriously? Aren't you a mechanic?

Drag Racing XL, 2wd, I launch at 2500, 3000 depending on boost, ASS off, Traction Control off, Locker on…Quarter Mile no binding or problems, lights both rear tires, locker light comes back at 20 -25 mph at the turnoff…
So far no problems at over 100 runs..
Regards
Doc

Good thing you picked up a second one. That way you'll have something to drive when your next track day "grenades" your diff.

Loading. Cross loading the differential. Those gears definition of 'straight' is sitting on a table and turing exactly at the same rate. exactly. Your truck driving 'straight' down a road is Not mechanical table straight, so your still going to cross load the diff. The amount of loading you're gonna do no one can say, it's Unpredictable. But the further you drive the greater the variance the greater of the loading. Eventually the stress Hass to be released, 99.9% of the time a tire will spin sometimes a gear will fail. You could probably get away with it for quite a long while before you the fatigue the gears enough.

Very good explanation. Italicized and edited the most important part.

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