Locker questions (and preference poll)

[campfire]

That sounds fishy to me.... Whats the purpose of them even selling them if they act like an open diff......?

That's what I'm getting at. Eaton's claim for the Truetrac is that, when one wheel is freely spinning, the helical gears will bind, and both axle shafts will lock together until the gears unbind. They even have animated film clips detailing how each of their lockers function. I should be able to jack up a wheel and drive away with just one wheel touching the ground. This should be true for any of the locker options, including the posi units. If not, why bother with them?

 

[dyeager535]

Gov-lock uses clutch disks, but they are metal of some sort I believe. The clutch portions I've seen from them are not faced with a material, the metal used is the clutch.

This must be an Eaton video, not done watching it yet. But it's the gov-lock displayed/explained:

Edit: The other designs work great on FLAT ground, with HIGH traction surfaces. Posi/truetracs are good choices for the STREET because they are pretty much invisible to the driver, and are not expected to handle one tire off the ground situations. You don't feel them turning, and they provide additional grip when accelerating. There is a truetrac video from eaton on youtube as well, note that they don't show any diagram of 0% on one axle, which is what it would be in the air, and I'd assume with one tire on ice. Most of the traction aids in the automotive world are not geared towards people that get tires in the air. Otherwise there would be no reason for real lockers, everyone would run a truetrac.

Edit edit: The gov-loc's bad reputation comes primarily from the 8.5 (and probably 8.625") versions. The carriers aren't real strong, and things such as larger tires, more power, or high traction surfaces generate more force than the carrier can withstand when the mechanism locks. The 9.5's don't seem to have the same issue (everything is larger) and I don't recall hearing of but one gov-lock failure in the 10.5" diffs. I honestly don't know if the 10.5's operate the same way, because from what I've seen, the carriers are completely different than the 8.5/9.5 versions.

 

[sweetk30]

mrk5 has it on the money in my opinion .

stock g80 gov loc and save for arb or grizzly air locker later on .

and what gear ratio ? I have a new nos gov loc for 4.56-up .

years of beating on my 14ff gov loc units I love them hands down for dd/moderate 4x4 like you are saying .

I voted gov loc and other for air locker .

 

[campfire]

Gov-lock uses clutch disks, but they are metal of some sort I believe. The clutch portions I've seen from them are not faced with a material, the metal used is the clutch.

This must be an Eaton video, not done watching it yet. But it's the gov-lock displayed/explained:

Edit: The other designs work great on FLAT ground, with HIGH traction surfaces. Posi/truetracs are good choices for the STREET because they are pretty much invisible to the driver, and are not expected to handle one tire off the ground situations. You don't feel them turning, and they provide additional grip when accelerating. There is a truetrac video from eaton on youtube as well, note that they don't show any diagram of 0% on one axle, which is what it would be in the air, and I'd assume with one tire on ice. Most of the traction aids in the automotive world are not geared towards people that get tires in the air. Otherwise there would be no reason for real lockers, everyone would run a truetrac.

Thanks for the video. Comparing that to this video for the Eaton Posi, it looks like the only difference is the absence of the 2 governor units that control when the unit is activated. That is, the Eaton Posi unit doesn't wait for 100RPM of differential before it activates, and it isn't disabled above 25MPH. Aside from that, the two units look pretty similar. Unless I'm missing something.

FWIW, here is an Eaton video for the Truetrac. They do animate what an asphalt/ice combination looks like with that locker. At the very least, it gives the impression that it is a match for such terrain.

I assumed the difference between real lockers and street lockers was durability. And I assumed, since I'm a gentle driver who does not run huge tires or scale rock piles, with a truck that is several thousand pounds lighter than its rear axle rating would allow, that I'm not in much danger of breaking stock-strength components. I might be overestimating things, but this is a forest trail truck, not a Moab crawler. Probably any unit offered for the 10.5" axle will be overkill for my application (strength-wise). I'm primarily concerned with what will function well in the handling department. So far I think we've gotten negative votes for everything except the Gov-lock. Funny enough, as that is what I originally planned to run (before I found out that I don't actually own one).


My question, since I don't have a G80, and I do have the option of cheaply buying the older Eaton unit, what is the functional difference between them? Would I be able to recover from a wheel on ice if I went with that unit, or would I always be wishing for some other unit? Would it be running out of lifespan if I didn't rebuild it prior to usage? Is this just a bad idea in general?


Thanks for all the input, guys. Keep it up.

 

[dyeager535]

I don't run moab, I blew my 8.5" gov-lock apart on the street turning the corner in front of my house.There is no question the 8.5" version is weak. 10.5" gov-lock, no question its pretty darn stout.

If you look at the GM test procedure for a posi, it's jack one tire off the ground and see how much torque it takes to turn it. Working properly it will take a minimum of X ft lbs to turn because the springs keep the clutches engaged all the time. Resistance to rotation causes the tire to *slip*. Since you can force the tire to slip with hand tools, imagine the force a 5000lb+ truck can exert and how likely it would be to provide usable traction. Do the same thing with a gov-lock and there is no resistance to rotating the tire in the air. Unless you turn it 100RPM, which is pretty tough to do by hand.

I really think in a truck, you'd have no idea whether or not the posi was helping or not. At least with a locker/gov-lock, you KNOW both tires are providing traction whether or not its what you need to keep moving.

 

[campfire]

mrk5 has it on the money in my opinion .

stock g80 gov loc and save for arb or grizzly air locker later on .

and what gear ratio ? I have a new nos gov loc for 4.56-up .

years of beating on my 14ff gov loc units I love them hands down for dd/moderate 4x4 like you are saying .

I voted gov loc and other for air locker .

The ARB has cool factor, but I'm not sure that I'll ever want to spend the big bucks for one. To me, it's only a little bit cooler than an automatic locker, and it's a whole lot of extra cost. I'd probably be happier off putting the money into a Webasto unit if I were to be dropping that level of coin. Probably get used more often around here.

Unfortunately for your NOS unit, I'm planning to run 3.73 gears. Otherwise you'd have a PM waiting for ya.

 

[campfire]

I don't run moab, I blew my 8.5" gov-lock apart on the street turning the corner in front of my house.There is no question the 8.5" version is weak. 10.5" gov-lock, no question its pretty darn stout.

Yeah, I'm not planning to run the 8.5" G80. Already replaced the one in Big Blue. And this axle rebuild is happening because the P.O. got halfway through swapping in the 14bff...which was being installed because this truck's 8.5" G80 carrier disintegrated. So I have a 100% failure rate when it comes to 8.5" G80 units.

 

[campfire]

If you look at the GM test procedure for a posi, it's jack one tire off the ground and see how much torque it takes to turn it. Working properly it will take a minimum of X ft lbs to turn because the springs keep the clutches engaged all the time. Resistance to rotation causes the tire to *slip*. Since you can force the tire to slip with hand tools, imagine the force a 5000lb+ truck can exert and how likely it would be to provide usable traction. Do the same thing with a gov-lock and there is no resistance to rotating the tire in the air. Unless you turn it 100RPM, which is pretty tough to do by hand.

Good point. Though the posi clutches aren't engaged very much when just sitting (they're further activated by wheel spin, right?). So I'm not sure it's valid to say that it can't be providing good traction in that situation just because it's barely engaged when sitting.

I really think in a truck, you'd have no idea whether or not the posi was helping or not. At least with a locker/gov-lock, you KNOW both tires are providing traction whether or not its what you need to keep moving.

This is probably true. I had no idea that I owned a G80 until it was time to replace the pinion seal. When it was opened up the carrier was full of spider cracks. That was my first indication that I had such equipment. It probably did not function, as I did get stuck once with one wheel to spinning on ice)

Even after it was replaced (with another G80 ), I can't point to any occasions where it has ever been needed, nor do I know what it feels like having the gov-lock engage.

Does it suddenly slam the shafts together when the differential reaches 100RPM, or is the engagement gradual?

 

[Ned Kelly]

I've had a Detroit in my K30 for 25yrs (auto trans). Snow and icey roads/highway experience....yes, it can drift on you sometimes on a winter highway, and it happens instantly when least expected...even the odd straight sections (when icey), never mind on a gentle highway turns. As you know, sometimes in the winter a driver doesn't always see the ice until you are on it. I just let off the throttle instantly, but you have to react quick. With your shorter wheelbase and standard trans, and if you plan on winter highway use, I would strongly vote for an ARB. Yes, pricey, but if it saves you from ONE highway spin out it is worth it. Who knows what can happen in that one incident...walk away only shaken, off the road (damage/rollover, etc.), or a drift into oncoming traffic?

You'll have the best of both worlds...predictable safe manners on road, and ultimate traction offroad. I guarantee you your will be much more relaxed in winter driving with the ARB in the back, and if the weather is so bad (snowstorm! yay!) that you need the ARB locked up on the highway, you'll be driving slow anyways.

From pricing perspective the ARB is maybe $150 or so more than the Yukon/Zip air locker? I would go with the ARB over the other air locker. Check out the destructive testing on youtube for ARB vs the other air locker.

I love the Detroit, but for your use there is an excellent option.

 

[beags86]

I voted for the gov loc for your application, but I think when I am ready I will pull the trigger on an ARB for myself. Its worth it to have options.

 

[runamok151]

I love the powertrax in my blazer which was a DD and weekend player. Very streetable in all weather and it's worked very well off road. That includes the occasional trip to Paragon (RIP) and Rausch Creek for some of the milder rock crawling, snowy hill climbs, a little mudding. It clicked occasionally going around corners, but two bottles of GM friction modifier stopped any noise.

 

[dyeager535]

Good point. Though the posi clutches aren't engaged very much when just sitting (they're further activated by wheel spin, right?). So I'm not sure it's valid to say that it can't be providing good traction in that situation just because it's barely engaged when sitting.

AFAIK with most/all posi-type units, there is no difference in how tightly the clutches are engaged whether driving or sitting. The ratings I had seen with the Eaton units prior was spring pressure. More spring pressure, more torque required to overcome that pressure. Spring pressure is all that holds the clutches together, and because the tires can exert enough force turning on the clutches, they "slip" and aren't normally noticeable for the driver. You may spin around on poor traction surfaces, but that is because the tires don't have anything to hold onto.

Does it suddenly slam the shafts together when the differential reaches 100RPM, or is the engagement gradual?

Yep, slams them together. It's on/off. Thus why the carriers come apart. One axle isn't turning, or is turning slower than the other, and wham, the carrier has to bring the other tire up to the same speed instantaneously. Thus why larger tires and more power hurt them. You may not have noticed it working due to wheelspeed. Eaton video says 20MPH and over they don't work, so if wheelspeed (not vehicle speed) exceeds that, it reverts to single wheel. Have to try it just above idle and have someone watch both tires.

 

[sweetk30]

once you have a gov-loc and know its there and how you use it / and how it works your good to go .

its people who think its a LOCKER and hard core that blow them up . or some who just hold the gas when spinning and don't let it click in nice and easy .

 

[black dawg]

Had a detroit in the rear of my burb for two winters now, most of the time I forget that it is there.

Did have one time though on a slippery interstate, that I was driving much slower than everybody else, because the suburban just felt weird (like I could loop it at any moment). Turned out a rear tire was 5psi low. with the air equal it felt normal.

As far as unexpected sliding or unpredictable handling on slippery roads, none of that.

 

[campfire]

AFAIK with most/all posi-type units, there is no difference in how tightly the clutches are engaged whether driving or sitting. The ratings I had seen with the Eaton units prior was spring pressure. More spring pressure, more torque required to overcome that pressure. Spring pressure is all that holds the clutches together, and because the tires can exert enough force turning on the clutches, they "slip" and aren't normally noticeable for the driver. You may spin around on poor traction surfaces, but that is because the tires don't have anything to hold onto.

Yikes. Lemme see if I have this straight. With a Detroit, you're constantly slipping rubber through corners, and with a posi unit you're constantly slipping those clutches. Is there some solution that doesn't involve constantly slipping all the time? Powertrax and Truetrac are starting to sound nicer.

Yep, slams them together. It's on/off. Thus why the carriers come apart. One axle isn't turning, or is turning slower than the other, and wham, the carrier has to bring the other tire up to the same speed instantaneously. Thus why larger tires and more power hurt them. You may not have noticed it working due to wheelspeed. Eaton video says 20MPH and over they don't work, so if wheelspeed (not vehicle speed) exceeds that, it reverts to single wheel. Have to try it just above idle and have someone watch both tires.

I have not felt any such jerks during my driving. But I haven't needed the Gov-lock since before it was replaced.

 

[Ned Kelly]

black dawg makes a good point on tire pressures should be equal.
I forgot to mention that the times when my back end wanted to get squirrelly was when I was running empty or very little weight in the back. With some load and weight in the back all is good....like in a Suburban.
Again, when icey or black ice is encountered on the highway are the only times.

 

[campfire]

once you have a gov-loc and know its there and how you use it / and how it works your good to go .

its people who think its a LOCKER and hard core that blow them up . or some who just hold the gas when spinning and don't let it click in nice and easy .

I think you should qualify this statement. I absolutely babied my truck, almost never left pavement, never had the gov-lock engage, and still found myself with cracks running through my 8.5" carrier. A lot of other folks have had similar stories. No abuse was necessary.

I'm going to assume that your statement applies to only the 10.5" and 9.5" gov-lock carriers.

 

[dyeager535]

Yikes. Lemme see if I have this straight. With a Detroit, you're constantly slipping rubber through corners, and with a posi unit you're constantly slipping those clutches. Is there some solution that doesn't involve constantly slipping all the time? Powertrax and Truetrac are starting to sound nicer.

I have not felt any such jerks during my driving. But I haven't needed the Gov-lock since before it was replaced.

I don't have a detroit. My understanding of how they operate is that if you COAST through a corner, you aren't slipping anything...it's "unlocked". If you hit the throttle while turning, it will lock, and to some degree you will induce tire scrubbing. Most people say they don't really notice it causing massive tire wear or anything.

Gov-lock and the helical units are the only ones that aren't slipping to some extent, that aren't true lockers. I think you are worrying about wear too much. The Eaton posi units work for decades. But I don't think that's an issue, GM saw fit not to use the clutch style limited slip in trucks, only gov-locks, so that should tell you something about posi applicability in a heavy vehicle.

I've only felt the gov-lock when I spun the tires from a stop or very slow speed, and since the wheel spin means you have minimal traction in the first place, the engagement isn't brutal. Normal driving you'll never notice it, because it's not locking up.

I don't think the truetrac would be bad for mild wheeling, but what do they cost vs. a gov-lock carrier or complete axle assembly? You'd be one of the first on here I've heard of that will run a truetrac. Still not sure how you'd know it was working.

 

[6872xtc]

From what I have read and experienced with my truetrac, it will not act like an open diff. It is a torque biasing differential. From what I have seen, it will send a certain amount to each side, but it takes pressure from both sides to give the highest ratio of torque split. This is why in crawling, it needs some drag from the brakes to transfer some of the power. Not great for rock crawling.
We go elk hunting up at the 9K or so elevation at the first of November, I have run around in my shortbed on snowpack ed roads, and some with 4 or more inches of powder on top. 2wd was easy for a majority of it. The Detroit equipped Bronco that I drove, wouldn't go straight in powder, 2wd, and wouldn't go around long corners in 4wd without playing with the gas pedal.

My old G80, was not a problem on snow pack, and I saw it work perfectly on some obstacles in Moab.

I see lots of good input in this thread.

 

[Bent77]

Mrk5 hit it.

From your responses thats how i voted.
Having said that, my last and next build will be with a Detroit