Will I regret no limited slip?
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Joined: Oct 2005
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From: Way South
"Working as designed" is-- you have an open diff that we charged you for a posi!!
Looking at the '03 service manual they show worm style pinion gears similar to Detroit/Eaton Tru Trac
with some type of "brake shoe". In my case I remember seeing helical cut gears like you'd see in an automatic planetary gearset.
Since DC says there no problem I might have to take the thing apart and see what makes it work.
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Joined: Nov 2005
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From: Pattonville, Texas
I understand the frustration with the AAM limited slip diffs, but they do what they're designed to do - just go about it a different way. The Dana 80 in my other Ram has clutches in the rear that "preload" the axles together, and the AAM under certain conditions could benefit from such "preload", which is why apply the brakes usually does the trick...
Both axles are great - I have and use both, but as an analogy, it's pointless to get upset at a beam-type torque wrench when you're accustomed to listening for the "click"...
I like the operating simplicity of the Dana - no brakes required!
I like the low maintenance of the AAM - no posi adjustment/wear.
I've found the AAM to be so much more limited in slip as to greatly increase rear tire wear over the Dana scheme - and the '05 will definitely get sideways much easier on slick surfaces...
Both axles are great - I have and use both, but as an analogy, it's pointless to get upset at a beam-type torque wrench when you're accustomed to listening for the "click"...
I like the operating simplicity of the Dana - no brakes required!
I like the low maintenance of the AAM - no posi adjustment/wear.
I've found the AAM to be so much more limited in slip as to greatly increase rear tire wear over the Dana scheme - and the '05 will definitely get sideways much easier on slick surfaces...
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Joined: Jun 2006
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anti-spin apples and oranges
Lots of folks seem to be bashing the AAM Trac Rite in comparison to other technologies that are just plain different.
Some anti spins-- the typical "posi" units, have friction clutches that bascially drag against the differential's function. They can only do so much to prevent spin, and the clutches tend to wear out long before the vehicle. They probably have their use for daily driver hot rods, but even there, it's an obsolete design.
The GM units are an Eaton with swing weights and pawl clutch that normally operates as a 100% open differential, but if it senses spin, suddenly acts to engage a full lock (during spin- wham). Probably works great at suddenly launching you out of stuck situations, but they have a reputation for failing catastrophically without warning if you run a lot of torque through them often: _bad_ match for a CTD.
Lockers: great if you really know what they involve and are sure you want it (for serious off-roading). Would you want a locker for on-road driving in slippery winter conditions? I wouldn't. You end up choosing between a loose open differential (no thanks) and a totally locked unit that you really can't drive on pavement, or that may send you out of control from running 100% locked on slippery surfaces.
The AAM Trac Rite helical gear unit is a torque proportion-ing descendent of the "Torsen" technology. The helical gears function as a sort of "intelligent" mechanism. Within limits (I think about a 3:1 ratio) it will send more torque to the wheel with more traction; if traction shifts, it re-adjusts itself on the fly with no operator intervention. It responds dynamically, very quickly, so that if one wheel suddenly gains more traction, it sends the traction there. Because it can only do this up to a certain ratio, it won't move the vehicle if you lift one wheel off the ground Nothing but a full locker really will do that without destructive effects in the process. When one wheel has hopelessly lost traction, applying a little brake will help if one wheel has no traction at all-- you bring the ratio back within the 3:1 or so that it can respond to. And it doesn't have clutches to wear out, or pawl mechanisms to suddenly shred. To my mind, this represents the best option for a vehicle that you largely drive on pavement, but which you want to have good traction in slippery and gummy conditions that fall short of heroic boulder-climbing.
If you are only on pavement and not in the snow belt, skip both the anti spin and the 4X4. If you are in the snow belt and drive mostly on some form of maintained or semi-maintained roads but are not going to hurl your truck over boulders, the DC/ AAM factory anti spin is, to my mind, for most drivers and driving conditions, worlds ahead of the stock anti spins from Ford or GM, or the electric lockers. If you don't care about a vehicle that is driveable on the road in ugly winter or muddy back road conditions, but feel compelled to drag your truck over boulders, get a full locker.
Some anti spins-- the typical "posi" units, have friction clutches that bascially drag against the differential's function. They can only do so much to prevent spin, and the clutches tend to wear out long before the vehicle. They probably have their use for daily driver hot rods, but even there, it's an obsolete design.
The GM units are an Eaton with swing weights and pawl clutch that normally operates as a 100% open differential, but if it senses spin, suddenly acts to engage a full lock (during spin- wham). Probably works great at suddenly launching you out of stuck situations, but they have a reputation for failing catastrophically without warning if you run a lot of torque through them often: _bad_ match for a CTD.
Lockers: great if you really know what they involve and are sure you want it (for serious off-roading). Would you want a locker for on-road driving in slippery winter conditions? I wouldn't. You end up choosing between a loose open differential (no thanks) and a totally locked unit that you really can't drive on pavement, or that may send you out of control from running 100% locked on slippery surfaces.
The AAM Trac Rite helical gear unit is a torque proportion-ing descendent of the "Torsen" technology. The helical gears function as a sort of "intelligent" mechanism. Within limits (I think about a 3:1 ratio) it will send more torque to the wheel with more traction; if traction shifts, it re-adjusts itself on the fly with no operator intervention. It responds dynamically, very quickly, so that if one wheel suddenly gains more traction, it sends the traction there. Because it can only do this up to a certain ratio, it won't move the vehicle if you lift one wheel off the ground Nothing but a full locker really will do that without destructive effects in the process. When one wheel has hopelessly lost traction, applying a little brake will help if one wheel has no traction at all-- you bring the ratio back within the 3:1 or so that it can respond to. And it doesn't have clutches to wear out, or pawl mechanisms to suddenly shred. To my mind, this represents the best option for a vehicle that you largely drive on pavement, but which you want to have good traction in slippery and gummy conditions that fall short of heroic boulder-climbing.
If you are only on pavement and not in the snow belt, skip both the anti spin and the 4X4. If you are in the snow belt and drive mostly on some form of maintained or semi-maintained roads but are not going to hurl your truck over boulders, the DC/ AAM factory anti spin is, to my mind, for most drivers and driving conditions, worlds ahead of the stock anti spins from Ford or GM, or the electric lockers. If you don't care about a vehicle that is driveable on the road in ugly winter or muddy back road conditions, but feel compelled to drag your truck over boulders, get a full locker.
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Joined: Oct 2005
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From: Way South
Great post? Great misinformation.
Sure clutch and spring style limited slip are probably the oldest technology but is still the dominate type. They are type available in RWD car applications from Corvettes, Camaro to Mustangs. I had over 400,000 miles on my '72 Suburban with style and it still worked great. Can you burn one up with mistreatment? Sure. Just like I can abuse your automatic transmission and burn up the clutches.
The Eaton GovLok does not work as a 100% open differential.
See the clutches? This differential works like a limited slip. If one axle manages to spin 50 rpm's more than the other the locking paw turns it into a locker. The governor unlocks the paw if the speed of the vehicle is over ~20mph. Then it is back to limited slip mode. I wouldn't call the GovLok robust but I wouldn't call it fragile. They definately have a reputation of exploding. But GM is notorious for it's undersize axles inthe 1/2 trucks and the GovLok doesn't like big, big tires and hardcore offroading. For most poeple they never give any problem.
Although gear type differnentials have their place (FWD ricers and AWD minivans) they can be designed to work with 4WD's. Here's a quote about the Torsen:
The Torsen (from Torque Sensing) works as an open differential when the amount of torque going to each wheel is equal. As soon as one wheel starts to lose traction, the difference in torque causes the gears in the Torsen differential to bind together. The design of the gears in the differential determines the torque bias ratio. For instance, if a particular Torsen differential is designed with a 5:1 bias ratio, it is capable of applying up to five times more torque to the wheel that has good traction.
These devices are often used in high-performance all-wheel-drive vehicles. Like the viscous coupling, they are often used to transfer power between the front and rear wheels. In this application, the Torsen is superior to the viscous coupling because it transfers torque to the stable wheels before the actual slipping occurs.
However, if one set of wheels loses traction completely, the Torsen differential will be unable to supply any torque to the other set of wheels. The bias ratio determines how much torque can be transferred, and five times zero is zero.
Because of design conficts with the 4 wheel anti lock brakes the torque bias is MUCH less for the AAM TracRite. They did the same in the Torsen II diffential that's installed in the civilian H1. The Torsen gets it share of complaints in the Hummer forums.
I complain only because others are coming from other brands that function well offroad. I've buried my '03 Dodge too many times in soft sand. I just want others to know it's limitations. I was hoping the '03 was going to be a good as my '01 or my previous gas Chevy truck at the ranch or the Texas coast but so far it has not.
Sure clutch and spring style limited slip are probably the oldest technology but is still the dominate type. They are type available in RWD car applications from Corvettes, Camaro to Mustangs. I had over 400,000 miles on my '72 Suburban with style and it still worked great. Can you burn one up with mistreatment? Sure. Just like I can abuse your automatic transmission and burn up the clutches.
The Eaton GovLok does not work as a 100% open differential.
See the clutches? This differential works like a limited slip. If one axle manages to spin 50 rpm's more than the other the locking paw turns it into a locker. The governor unlocks the paw if the speed of the vehicle is over ~20mph. Then it is back to limited slip mode. I wouldn't call the GovLok robust but I wouldn't call it fragile. They definately have a reputation of exploding. But GM is notorious for it's undersize axles inthe 1/2 trucks and the GovLok doesn't like big, big tires and hardcore offroading. For most poeple they never give any problem.
Although gear type differnentials have their place (FWD ricers and AWD minivans) they can be designed to work with 4WD's. Here's a quote about the Torsen:
The Torsen (from Torque Sensing) works as an open differential when the amount of torque going to each wheel is equal. As soon as one wheel starts to lose traction, the difference in torque causes the gears in the Torsen differential to bind together. The design of the gears in the differential determines the torque bias ratio. For instance, if a particular Torsen differential is designed with a 5:1 bias ratio, it is capable of applying up to five times more torque to the wheel that has good traction.
These devices are often used in high-performance all-wheel-drive vehicles. Like the viscous coupling, they are often used to transfer power between the front and rear wheels. In this application, the Torsen is superior to the viscous coupling because it transfers torque to the stable wheels before the actual slipping occurs.
However, if one set of wheels loses traction completely, the Torsen differential will be unable to supply any torque to the other set of wheels. The bias ratio determines how much torque can be transferred, and five times zero is zero.
Because of design conficts with the 4 wheel anti lock brakes the torque bias is MUCH less for the AAM TracRite. They did the same in the Torsen II diffential that's installed in the civilian H1. The Torsen gets it share of complaints in the Hummer forums.
I complain only because others are coming from other brands that function well offroad. I've buried my '03 Dodge too many times in soft sand. I just want others to know it's limitations. I was hoping the '03 was going to be a good as my '01 or my previous gas Chevy truck at the ranch or the Texas coast but so far it has not.
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Joined: Feb 2006
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From: West Virginia
Originally Posted by bigdav160
Great post? Great misinformation.
Sure clutch and spring style limited slip are probably the oldest technology but is still the dominate type. They are type available in RWD car applications from Corvettes, Camaro to Mustangs. I had over 400,000 miles on my '72 Suburban with style and it still worked great. Can you burn one up with mistreatment? Sure. Just like I can abuse your automatic transmission and burn up the clutches.
The Eaton GovLok does not work as a 100% open differential.
See the clutches? This differential works like a limited slip. If one axle manages to spin 50 rpm's more than the other the locking paw turns it into a locker. The governor unlocks the paw if the speed of the vehicle is over ~20mph. Then it is back to limited slip mode. I wouldn't call the GovLok robust but I wouldn't call it fragile. They definately have a reputation of exploding. But GM is notorious for it's undersize axles inthe 1/2 trucks and the GovLok doesn't like big, big tires and hardcore offroading. For most poeple they never give any problem.
Although gear type differnentials have their place (FWD ricers and AWD minivans) they can be designed to work with 4WD's. Here's a quote about the Torsen:
The Torsen (from Torque Sensing) works as an open differential when the amount of torque going to each wheel is equal. As soon as one wheel starts to lose traction, the difference in torque causes the gears in the Torsen differential to bind together. The design of the gears in the differential determines the torque bias ratio. For instance, if a particular Torsen differential is designed with a 5:1 bias ratio, it is capable of applying up to five times more torque to the wheel that has good traction.
These devices are often used in high-performance all-wheel-drive vehicles. Like the viscous coupling, they are often used to transfer power between the front and rear wheels. In this application, the Torsen is superior to the viscous coupling because it transfers torque to the stable wheels before the actual slipping occurs.
However, if one set of wheels loses traction completely, the Torsen differential will be unable to supply any torque to the other set of wheels. The bias ratio determines how much torque can be transferred, and five times zero is zero.
Because of design conficts with the 4 wheel anti lock brakes the torque bias is MUCH less for the AAM TracRite. They did the same in the Torsen II diffential that's installed in the civilian H1. The Torsen gets it share of complaints in the Hummer forums.
I complain only because others are coming from other brands that function well offroad. I've buried my '03 Dodge too many times in soft sand. I just want others to know it's limitations. I was hoping the '03 was going to be a good as my '01 or my previous gas Chevy truck at the ranch or the Texas coast but so far it has not.
Sure clutch and spring style limited slip are probably the oldest technology but is still the dominate type. They are type available in RWD car applications from Corvettes, Camaro to Mustangs. I had over 400,000 miles on my '72 Suburban with style and it still worked great. Can you burn one up with mistreatment? Sure. Just like I can abuse your automatic transmission and burn up the clutches.
The Eaton GovLok does not work as a 100% open differential.
See the clutches? This differential works like a limited slip. If one axle manages to spin 50 rpm's more than the other the locking paw turns it into a locker. The governor unlocks the paw if the speed of the vehicle is over ~20mph. Then it is back to limited slip mode. I wouldn't call the GovLok robust but I wouldn't call it fragile. They definately have a reputation of exploding. But GM is notorious for it's undersize axles inthe 1/2 trucks and the GovLok doesn't like big, big tires and hardcore offroading. For most poeple they never give any problem.
Although gear type differnentials have their place (FWD ricers and AWD minivans) they can be designed to work with 4WD's. Here's a quote about the Torsen:
The Torsen (from Torque Sensing) works as an open differential when the amount of torque going to each wheel is equal. As soon as one wheel starts to lose traction, the difference in torque causes the gears in the Torsen differential to bind together. The design of the gears in the differential determines the torque bias ratio. For instance, if a particular Torsen differential is designed with a 5:1 bias ratio, it is capable of applying up to five times more torque to the wheel that has good traction.
These devices are often used in high-performance all-wheel-drive vehicles. Like the viscous coupling, they are often used to transfer power between the front and rear wheels. In this application, the Torsen is superior to the viscous coupling because it transfers torque to the stable wheels before the actual slipping occurs.
However, if one set of wheels loses traction completely, the Torsen differential will be unable to supply any torque to the other set of wheels. The bias ratio determines how much torque can be transferred, and five times zero is zero.
Because of design conficts with the 4 wheel anti lock brakes the torque bias is MUCH less for the AAM TracRite. They did the same in the Torsen II diffential that's installed in the civilian H1. The Torsen gets it share of complaints in the Hummer forums.
I complain only because others are coming from other brands that function well offroad. I've buried my '03 Dodge too many times in soft sand. I just want others to know it's limitations. I was hoping the '03 was going to be a good as my '01 or my previous gas Chevy truck at the ranch or the Texas coast but so far it has not.
So for all the people you are trying to educate, I think that 99% of them would be happy with what these trucks have to offer right out of the box.
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Joined: Nov 2005
Posts: 7,785
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From: Pattonville, Texas
bigdav160 - what "great misinformation" on PYBYR's great post? You essentially made the same points he did...
I was wondering how you buried your '03 Dodge (Ram?) in the soft sand "so many times" - did you dig the hole by spinning the tire(s?) or what?
Both of my Rams perform very well off-road, but I obviously don't expect them to fjord a mudbog, go rock-crawling, or get through deep beach sand.
I think the problems people have getting stuck in their Rams have more to do with how their vehicle is setup and their driving technique more than whether they have clutches or gears in the rear.
I was wondering how you buried your '03 Dodge (Ram?) in the soft sand "so many times" - did you dig the hole by spinning the tire(s?) or what?
Both of my Rams perform very well off-road, but I obviously don't expect them to fjord a mudbog, go rock-crawling, or get through deep beach sand.
I think the problems people have getting stuck in their Rams have more to do with how their vehicle is setup and their driving technique more than whether they have clutches or gears in the rear.
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Joined: Apr 2005
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From: Alpena MI
AAM is crap design, give me a friction type axle any when you get off road. A REAL truck will put some torque to the wheel which has the traction. What purpose is the anti-slip serving when one wheel is on ice (or hung up on the axle) and spining freely, while the other has the abiltiy to provide some traction!!!!!
Oh I know a couple on this site will say its the way you drive, you don't know how to drive, LOL. What a joke. Well yea, if you stay on the pavement and leave black marks, it works as advertised. This is the worst off road truck I have ever had, PERIOD. But the best highway ride of them all.
Oh I know a couple on this site will say its the way you drive, you don't know how to drive, LOL. What a joke. Well yea, if you stay on the pavement and leave black marks, it works as advertised. This is the worst off road truck I have ever had, PERIOD. But the best highway ride of them all.
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Joined: Apr 2005
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From: Alpena MI
XLR8R--Take all polls you want, untill you traveled in the tracks of the guys that have posted here you probably have no idea the capabilites a 4X4 (diesel or gasser has is the real nasty stuff) or else you would know better than to make those comments. As they say some talk the talk others walk the walk.
Enough said about this topic, apparently the AAM works for some and not for others, now the poster can filter through the feedback. To ALL have a nice labor day week-end.
Enough said about this topic, apparently the AAM works for some and not for others, now the poster can filter through the feedback. To ALL have a nice labor day week-end.
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just got me out of the slimy weeds
OK, out of academic interest, just went to a bonfire & beer party, and the easiest parking spot was with the driver's side wheels on gravel road, and passenger side wheels in a slimy weedy ditch. It's been really rainy here lately. Can a situation get any worse for traction? Knew someone could pull me out if push came to shove, so decided it was a great chance to put theory to test... Running stock non-agressive BFG Rugged Trail (ha ha) tires. Went to leave, and the AAM Trac Rite walked the truck right on out without a hint of spin, and no need to engage 4 wheel drive. With the torque these HO versions have, that is nothing short of exceptional. Sure, you want a real locker and can afford it-- go for it! But if you want traction and don't want to pay a bundle or take your axle apart, this AAM Trac Rite works better than any other factory variation that I have driven, and I've been fooling with vehicles since I was a semi-delinquent teenager and had a full head of hair-- a long time ago. If the choice is, as the original person who started this thread asked, whether to get the anti-spin or not, it's a no brainer to me. The only down side I see to the anti-spin is that it can present weird handling on washboarded gravel. The anti spin feature makes it hop and dance even more than usual on washboards.
PS XLR8R & others, thanks for the compliments on my prior "apples and oranges" observations. I am not an enginerd, but play one by night and weekend. I invite ideas on how to to quit my desk job and yet earn income support my recommended daily dose of iron, pay my mortgage, and feed my kid!
best regards to all, even those who differ in opinion
PS XLR8R & others, thanks for the compliments on my prior "apples and oranges" observations. I am not an enginerd, but play one by night and weekend. I invite ideas on how to to quit my desk job and yet earn income support my recommended daily dose of iron, pay my mortgage, and feed my kid!
best regards to all, even those who differ in opinion
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Joined: Feb 2006
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From: West Virginia
Originally Posted by lt11le
Hey Dan Marino, You have a locker in the front of your truck??
What kind is it? Where did you get it from?
What kind is it? Where did you get it from?
I bumped it up last week it shouldnt be to far down in the threads.
Thread Starter
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Joined: Aug 2006
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From: Fort Collins, CO
Thanks everybody for the replies. I certainly didn't intend to start a debate, but have learned a lot from the thread. I ended up getting the non-limited slip truck, pretty much just because that's the only '06 I could find like I wanted (w/exception of limited slip) and didn't really want to get an '07. Maybe if I end up regretting my decision, someone will eventually make an aftermarket option for this rear-end. I find it hard to believe they don't already!!!
Thanks again.
Thanks again.