Set Me Straight...

[DaveHess]

My '03 has the 11. 5 AAM with the Trac-Lok. My understanding was (is) as the traction wheel begins to spin, it forces the gears in the Trac-Lok to slide to the opposite wheel and ultimately engage both wheels. Is that true? Does that mean that I drive most of the time as a 1 wheel wonder? Also, I have a neighborhood buddy with a '06 LBZ Duramax with the 11. 5 AAM and he is telling me his is driving both rear wheels at all times and that the "posi" in his is electronically controlled. If that was true, why the electronic control if both wheels are always driving? Somebody please set me straight on this...

 

[JApol]

if you are driving down a slick road and you feel the back end moving side to side, that is the differential moving the power from side to side.
If you are stuck in the mud or slow you are a one wheel peeler. To counteract this put moderate pressure on the brakes and it will "fool" the diff to put power to both wheels allowing you to use both back tires.
Your front diff is open.

 

[RVTRKN]

I'm not sure about the GM, but if he can electronically turn it off and on then it probably is true and its not considered to be a limited slip differential. Limited slip means that when the traction side slips the other will engage. Only if you do extreme 4X4ing does it make a real difference, and if you do, install the Detroit Lockers on yours. The Dodge Power Wagon has this as a standard option but in the front as well and only because the CTD is not an option for it, is why I wouldn't consider one. You may not be aware of the fact that the GM truck does not have a solid axle in the front and if you install lockers on both your front and rear he will not have a chance of keeping up with you, not that you couldn't with your LSD.



I watched from a distance (I was on my Harley) at a group of people trying to get a D/M out of a creek, stuck with the front end partially submerged with a couple of Fords trying to pull him out. The funny part was, they had him strapped to their rear hitches and would lose traction when they pulled on the D/M. I would have recommended the correct way but I was too far away and would have had to have rode my Harley into the 4X4 park. If they would of pulled him from their front hitches, the weight of the engine and the solid front axle should have done the trick. They left him there in the creek and I never saw the rescue, it had taken them about two hours of trying before they left. I had to finish my ride through the hills before it got dark, so I never saw how he got it out.

 

[RVTRKN]

if you are driving down a slick road and you feel the back end moving side to side, that is the differential moving the power from side to side.

If you are stuck in the mud or slow you are a one wheel peeler. To counteract this put moderate pressure on the brakes and it will "fool" the diff to put power to both wheels allowing you to use both back tires.

Your front diff is open.

Thats a good idea, I never thought about that.

 

[DaveHess]

I had heard of lightly applying the parking brake to "fool" the Trac-Lok. As for the electronic lock on the D-Max. He tells me it automatically engages with no input from him. I think he is full of ca-ca. I have an appreciation for anything diesel but this guy looks down his nose at my Dodge. He was telling me if he power brakes it that both wheels go up in smoke. I don't like to power brake my Dodge but I have jumped on it hard from standing still and left two tire marks where she spun up a little before gripping the ground. My dollar is he is also a one wheeled wonder until forced otherwise.

RVTRKN: I was aware of the front axle difference between the D-Max and my Dodge. With the D-Max guy I was trying to defend my Dodge with the truth as I know it and that just fueled his Chevy "superiority". You know how that goes. He is an avid "Diesel Power" reader and thinks every mod in that magazine is God-sent. I try to explain to him not to become a "trick of the week" club member but it is difficult.

 

[DaveHess]

So, what does a stock '06 LBZ Duramax have for a rear-end and by what mechanism does it become a "posi"? That is my question so when this discussion comes up again with my buddy, I can compare apples to apples.

 

[DaveHess]

Yeah Andres. 10-4 to that. My guess he has the same set-up as I do since they are both 11. 5" AAM axles. He does NOT have any electronic controls for his rear axle in the cab. No push button or switches what-so-ever for the rear axle. To me it seems he is just trying to better himself to my Ram. I see him sliding around corners up here in the snow and I'll follow him around the same corner with no sliding problem at all. Then he claims "it broke loose". My answer is always, "throttle control". My initial post was to look for anyone out there with an LBZ or experience with an LBZ truck and if they had direct knowledge of the type of "posi" is in the GM version of the 11. 5" AAM. I know what mine is, what's theirs.

 

[BILLVO]

Some systems use the antilock brake system for traction control system. It sees all 4 wheel speed sensors and if 1 wheel spins "X"% faster than the other the antilock system will automatically brake the wheel that is slipping to transfer power to the traction side. The GM and Dodge are the same. The torsen system will let one wheel start to spin and engage the other but it should never be a one wheel wonder if it is working it will engage the traction wheel within less than i revolution of the nontraction tire. Gm may use the limited slip and the traction control system together thus being electronically controlled

 

[KParsons]

locker

i had a locker in my 94 ford gasser. it was great to have . very rare did i ever feel it un lock. i will put one in my 06 dodge soon. kp

 

[BILLVO]

i had a locker in my 94 ford gasser. it was great to have . very rare did i ever feel it un lock. i will put one in my 06 dodge soon. kp

Is anyone building a locker for the AAM yet? I know they have been in R&D from detroit and ARB But I didn't think there was one on the market yet. Only option is the factory limited slip unless someone finally release one now. I haven't checked for a couple month as I am waiting for aftermarket to release one also and see what price comparison will be. Can buy a factory unit for 550 bucks.

 

[DPKetchum]

The D/max and the Dodge have the SAME rear setup. Slightly differant housings. Both are AAM Limited slips. Both the FRONTS are open diffs. If both are STOCK that is.

 

[rbattelle]

The Dodge axle uses this Trac-Rite differential.

Notice, however, that AAM offers 2 electronic versions of the same differential:
Trac-Rite EL, which looks to me like an electronic locker
Trac-Rite GTL, which looks like ours with the addition of the electronic locker.

I'd love to have either of those electronic ones - particularly the EL model, as it offers the simplicity of an open differential with the solid lockup of a locker. All at the flip of a switch.

According to the GM website, for $825 you can equip your rear axle with a "automatic locking differential", which gives us no indication of the type of locker being used. But I think it's reasonable to expect it's one of the electronic versions of the Trac-Rite linked above. Exactly which one, I'm not sure, but for $825 I would hope it's the GTL.

Obviously, GM, in their infinite "wisdom", feels their customers are too stupid to be given the ability to manually engage/disengage the locker, so they probably have it programmed into the computer.

Nevertheless, the argument with your friend is meaningless. Both trucks act like an open differential except when one wheel loses traction. Then - and only then - do they each engage some sort of mechanism for limiting the slip of that one wheel.

I would suspect that the full-lock mode of the GTL is commanded by the vehicle computer only at slow speed (probably under 5 or 10 mph) and only when 4wd is engaged (possibly only in 4wd lo). This might be done so that the vehicle doesn't decide to lock up the rear axle during an ordinary on-road turn. I don't know this for sure, I'm just speculating. If I'm correct, then both of your rear axles behave identically during normal driving conditions. His rear differential, however, would theoretically be superior during low-speed off-road maneuvering.

Now, if you really want to put this guy in his place, show him this photo!

Ryan

 

[RVTRKN]

Chain'em up or shut up

You can solve your dilemma by challenging him to a pull off, to prove how superior his D/M is, and then start pulling him all over the dirt lot with his friends watching as he gets embarrassed. Your advantage is more weight in the front due to your cast iron block and heads and the solid front axle. Your low end torque is far superior than his, when his max torque hits around the 2300-2500 RPM. This will cause him to lose traction because yours has already started pulling causing his traction to slip, and due to his high RPM, his wheels will only spin in vain. Another way to look at it, in his mind his higher HP will let him think he has the advantage when in reality it's his downfall.



There is a reason the critic's will admit to the stump pulling power of our CTD trucks and is why they are popular for hauling heavy loads up steep grades at the low RPM ranges.



I would also like to warn you at the same time, make sure your truck has had its service with your auto trany inspected. Before you challenge him, see if his diff has the same 3:73 rear as yours, as a 4:10 may help him or even the odds. And what I am recommending to you is extremely hard on your truck and all bets are off to the possibility of drive line breakage. Don't brag about your truck, just state the fact that your tired of hearing about it.



I heard the "my truck is better than yours" from a neighbor when I first bought my truck, I waited until he started to brag again around his friends, and thats when I said "CHAIN'EM UP OR SHUT UP", he chose to shut up. I really didn't want to do it but I figured I would nip it in the bud. I would have, if he didn't back down because I know of the stump pulling power of our CTD's and the advantages as stated above.



BTW, I don't remember which one of the Diesel's mags wrote about the comparisons when the LBZ higher HP first came out. But they did state that there is nothing better than the CTD working hard and for many of miles and pulling heavy up a grade.

 

[DaveHess]

RVTRKN: That's funny but truth be told, I wouldn't want to put myself in the situation of hurting my truck. I've tried to get him on a dyno with me but there is never enough "extra cash" to allow it. Hmmmm... . He's a decent guy to me but you guys have all heard the D-Max guys before. I can't remember which Edge product he is running but it is the one with the gauge pod on the A-Pillar. Oh, well.....

 

[MChrist]

Regarding the Tru Trak, I just had my mechanic install one in the rear of my '06 w/3. 73's. It wasn't limited slip equipped from factory, and horrible in snow! WAY better now. Also have 800# salt bags in the rear over the axle. I think I paid around $550. If anybody goes this route, be sure to order new bearings. The rep told me since I only had 35,000 miles, I wouldn't need new bearings. My mechanic had to order bearings because they get chewed up during removal, so make sure you get them.

 

[steved]

I didn't read the entire thread, but for the trac-rite to work, you need equal traction under both wheels to force the drive shoes together.

You can do the one-wheelie-peelie with the trac-rite just like an open diff if the surfaces are vastly different in traction under each wheel (bare pavement and ice). They are great on surfaces with equal traction, but they are also easy to overcome.

They are definitely not as good as the power-loc (D70) and trac-loc (D80) in the Danas because they are not preloaded... which you need to overcome the friction of the clutches to spin, not create friction by spinning to prevent a spin (counter-intuitive).

 

[brods]

It is probably a safe bet that your buddy has a G80 (gov loc) which has been used by GM for ages. In the old days the clutches wore out quickly. Now I think they use carbon fiber clutches for better longevity. The G80 only works at relatively low speeds. It has a counterweight that locks it out above some set rpms, iirc its works out to be like 20 mph?



Here is a good video, but don’t show it to your friend, lol. The action starts at 45 seconds: YouTube - Eaton Locking Differential Demonstration



I’d be curious to see if the furd and the Ram would make it with a little brake action (like Andres stated).