Home Forums Gear Hunting Trucks and Four-Wheel Drives Dodge axle

I have an 08 Ram 2500 with 4x4. It has the Anti-spin diff rear axle. I can find very little info on this axle. It doesn't operate like a limited slip. If I jack up the rear and spin a wheel, the wheels turn in opposite directions like an open diff. Yet, when I turn on gravel, I can feel 1 wheel sliding a little so I know it's not open. I do know that it holds the road very well on slick roads. At Christmas we put on 450 miles in 1 day, all on ice and snow, and it was flawless. Yet, it will allow 1 wheel to spin so it doesn't lock like limited slip.

Reading the various on-line forums & info sites, this thing seems to be a mystery on exactly what it is and how it works. Any hints?

This should explain your anti-spin rear differential. While your axle may not use this exact Eaton system, they are similar in operation.



I had a conversation with a Chevy technician a few years ago on how the rear locking action is accomplished and it is exactly as described in the video. Both Chevy and Dodge trucks use rear axles from AAM - American Axle Manufacturing.

Thanks. That gives me a better idea. I see that it doesn't engage when you're over 20 mph so you don't have it locked at highway speeds on ice. That's a good thing.

Doesn't GM call those the "Gov-Lock"?

The video shows the operation of a GM G80 rear locking differential and AFAIK it's only available on GM vehicles. I know for a fact that prior to 2003 (when I was still in the business) that Dodge had nothing like it.

The Dodge anti-spin dif was a limited slip dif and not an automatic locking dif. There's a big difference between the two. With a G80 once you break traction (below 20 mph) both rear wheels turn and never allow just one to spin. What Rock Chuck is describing "Yet, it will allow 1 wheel to spin" is a limited slip dif. It limits the slip but doesn't lock the rear axle.

Both Chevy and Dodge trucks may use rear axles manufactured by AAM but AFAIK they're not the same design. Like I said ... my knowledge is out of date and I'm not a professional mechanic so please correct me if I'm wrong.

I lifted 1 rear wheel with a little bottle jack and tried to drive it off the jack. If it limited the slip, it should have driven off the jack but it didn't. It just spun. Yet, when I turn on gravel, I can feel it doing something unlike an open diff. I'm trying to figure out what it's doing. In reading the various Dodge forums, I'm not the only one with this question. Lots of guys with it are asking the same thing but noone seems to know the answer.

This is a good demonstration of the practical aspects of different difs.

http://www.youtube.com/watch?feature=player_detailpage&v=q-rQTHMVAuw

The limited slip in your Dodge is a Trac-Rite.

It should be called anti-work as opposed to anti-spin because they suck.

I had the "anti-spin" axle in my '07 Ram 3500 SRW. Might as well have had an open diff. That thing was a POS.

The G80 in my Chevy 2500HD works 1000x better than Dodges LSD.

My 07 dodge has the factory locking rear. It locks up real well.

It doesn't matter how many websites you post this on,you still don't have a factory locker in your truck.

You were wrong on Ifish,and you're wrong here.

The G80 locker works exceedingly well for 99% of the drivers out there. If you are a 1%'er, you probably need full lockers front and rear. I have owned multiple trucks both with and without the G80 rear and it makes a big difference when off road or in the snow. In fact, a truck with it can go nearly as well in 2wd as a 4wd truck without. Not quite as well, but it is pretty close.

The G80 in the GM's is outstanding while the Dpdge "anti-spin" is probably the sorriest excuse of a limited slip ever built.

I've got a limited slip rear end in my 2006 Dodge.
A properly adjusted and setup limited slip will allow some of the energy expended to transfer over to the wheel with traction. But first the wheel which has lost traction must slip or spin a bit and allow the axle to transfer some of that lost energy. While it won't transfer very much of that lost energy, it should be enough to drive the truck off of a jack under one of the rear wheels.
A locking differential only allows both wheels to turn at the same speed.
One of the fascinating setups to me is the Tru-Trac. The more the wheel w/o traction slips, the more energy is sent to the other wheel. And a very smooth transition as well. E

I have a 2005 Dodge 2500 4 wheel drive with the limited slip rear end. I have played around in snow and ice doing what we used to call "Doing Donuts" and I can feel the rear end lock in after initial slippage. I have driven through some real slop but always engage 4WD when I know traction is going to get poor. These trucks are heavy (Cummins) and cannot be expected to run with a Jeep.

My Son has had several Jeep Rubicon's and they have the rear locker which is a whole new world of traction but they have a specific application. After watching what the Jeep crowd does to enhance performance I am convinced the After Market can provide whatever level of technology you need.

It is still a locking rear differential. Is it a full time locked up system? no. It locks up under load when one tire starts to spin. That is why the manufacturer calls it a locking rear differential. It locks up with equal power to each wheel until you let off the power. Then it acts as a drivable open rear. Go to AAM and look it up. Then maybe you will educate yourself

Since I started this thread, I've done quite a bit of reading on this factory Dodge Anti-slip axle. Dodge is silent on how it works and what to expect. It's hard to get any info at all on it. I did come up with this, though. It's not a limited slip and it's not designed for off road traction. It's designed for slick roads to keep the vehicle from spinning out. It appears to work very well for that. At Christmas we took a road trip of about 1600 miles, 700 of which were on really crappy ice and snow covered roads. This truck is a 4 door with a long bed and a manual transmission which is about as good as it gets for stability on snow. I used the 4x4 and we had new traction tires.

Even at that, my description of it's slick road handling would have to be superb. Every time I expected it to spin or slip some, it didn't. It held the road better than anything I've driven.

I think Dodge's refusal to give any info on this diff is giving many of us the wrong idea of what it's designed for. I still have no idea of how it works but it does work for it's intended purpose.

Ok, that's called "traction control" by lots of makers. Basically, it stops wheel spin by using the braking system to stop or slow the wheel that has lost traction as I understand it. It is often a standard item in all sorts of vehicles along with other electronic "baby sitter" type setups. All are designed to prevent an inexperienced driver from making a bad situation worse during bad driving conditions.
Dodge does offer a true, clutch pack, limited slip differential. I have one on my '06.
I've also owned a dodge truck with a true locked differential. It was a Detroit Locker that would have to unlock to allow me to make turns. They are still availiable as after market options.
The locking units commonly available as options are usually of the electric sort. You turn them on and they lock up under certain conditions. As a rule, if you go too fast or come out of low range, they unlock automatically. An exception is the Ford Raptor. It will stasy locked at speed.
Dodge also has a combination limited slip and fully lockable rear differential on their Power Wagons. Unlocked, it functions as a limited slip. Fully locked, it works like most of the others on the market. E

My 2004 dodge cummins has the American axle rear. I have 4:10-1 ratio.

With the stock tires which I only had for a weekend when new. I could spin both on dry pavement and leave two black rubber stripes behind the truck every time.

By the next weekend my toyo 38-13.50 tires were on. I could not smoke those in a straight line, and at the price I had no intention in trying very hard.

On occasion making a left turn in traffic I could get both to break free under hard acceleration and they will both lock doing that. In gravel the inside tire churns up the gravel just as a locker will.

I have ARB lockers on my old land cruiser. There is no difference in how the inner tire churns up gravel on a sharp turn. I know the dodge is not a locker. But it's ability to provide better then open diff traction is very noticeable.

I put in Detroit tru tracks in my Toyota pickup many years ago. They were excellent, but not lockers. This dodge rear axle reminds me very much of the way that tru-track axle worked.

I think one of the issues with the AA in the Dodge is that there is a wide range of tolerance, they can react differently from truck to truck. Some engage easily, some have to be power braked to get to work. My experience with my 2006 Cummins has been similar to JJHack's.