BEST REAR DIFFERENTIAL FOR 4x2 OR 4x4?

[TwoVans]

I have SMB's 4x4 package on my '09. My rear diff has 4.10 gears with the Ford OEM LSD. My front has the Detroit Truetrac LSD.

I have a fair amount of experience with lockers on my '06 Jeep Rubicon which is extensively modified and has seen duty across the Rubicon Trail in most conditions from some snow left in the spring to very dry in the fall and everything in between.

When deciding what to go with for my van, I was looking for the 99% solution with an emphasis on simplicity and reliability. I consulted many "experts" to include the folks at Dynatrac. The Detroit Truetrac came highly recommended for my front axle application.

I ordered my van with the Truetrac for both front and rear. During the build, I got a call from Heber informing me that the Truetrac was not compatible with my rear axle. I don't know if that is for all of the E-350 rear axles, or if there was something particular about my van's axle. Heber apologized for the confusion and offered to put a Ford OEM LSD in free of charge as it is a "throw-away part" for those of you that go with ARB lockers in the rear (by the way, thanks to the anonymous donor).

The advantage of the Truetrac vice a "normal" LSD is that it does not require any special oil or additives. Additionally, it does not have any parts that "wear" like the OEM does.

My experience driving with it: It works exactly as advertised. In other words, you cannot tell that it is there until the wheels start to slip. Even then, if I didn't know what to expect from an open diff, I wouldn't have noticed it was doing anything. I just didn't get stuck.

Obviously, driving with the front hubs unlocked, there is no impact as it is disconnected from the wheels.

I have done a fair amount of driving with the hubs locked while in 2wd to see if I could detect any handling anomalies. Again, I cannot detect anything up to and including highway speeds.

As far as driving with 4wd engaged at highway speeds. I personally would not do that. Period. From my perspective growing up in Minnesota winters, if the highway is slippery enough that you feel you need 4wd to make it, then slow speed is required. Again I have to emphasize - Period.

I do acknowledge that there are extreme situations where a locker would get you through and the LSD diffs might come up short. However, my Jeep experience tells me that they are EXTREMELY few and far between (and highly unlikely I will risk the van to get there). But hey, I spent a bunch of money to put winches in front and on the back - What's the point if I had lockers and never needed the winches???

Bottom line is this: It is working so well on the van that I am considering putting one in the front axle of my Jeep as my front locker is currently not working. For those that are familiar, it quit going up $1,000 hill the hard way on the Rubicon. I suspect the air hose simply came disconnected inside of the diff. However, it was that experience that got me heading in the direction I went with on the van. I couldn't be happier with it and would recommend it to anyone.

[NRL]

Not sure technically if it's 4x2, 4x4 or 4x2 plus, but I went the cheaper but it still works for me route.

I got a auto locker( Detroit/Powertrax) in the front with the Warn Premium Hub locks. So I opted to beef up the front and it's "on" only when I need it, when the rear LSD is not enough.

The hub locks used to be Warn Auto Hub locks but my buddy kept scaring me with the unlockable hub sceniro with Warn auto locks, I went with the premium manual hub locks. Nothing wrong with the auto warn hub locks the whole time I had it.. sure was nice not needing to get out of the van.

As for the lockers, Powertrax Auto-locker (doesn't seem to be the weaker No-Slip), had worked out great on my FJ80 and had proven itself to be effective for what I need it for sand, loose dirt, soft dirt, snow and everthing I think other then rock climbing and extreme ice.

Since the front is engaged only when I need it (Quigley 4x2 setup), it's quite effective compared to the stock 4x4 open diff setup.

The back diff is the normal factory LSD that came with factory Dana 60.

I guess I saved a few pennies compared to going with ARB Air Lockers or even the Eaton Electro-Magnetic LSD/Locker, but it was first the budget and to make sure nothing like electrical or compressed air based failures can cause the lockers to not lock when you need it. All that is needed is for the Borg Warner Transfer case to engage the front diff auto locker along with the manual hub locks locked to pull you out of a hairy spot that the rear can't get out of.

I thought off adding a detroit locker in the back to replace the factory LSD but I actually didn't need it in the rear. It's LSD which is something other then nothing but with the front lockers, I didn't think I needed it in the back also. If they were open diff only, I would have went with an auto locker (either Detroit or Powertrax) again.

The Detroit Locker or Powertrax Locker are quite effective traction aiding devices at a lower budget.

What I'm looking for is the difference between LSD and traction devices, like which ones are better. Some provide power to the wheel where there is traction and some provide power to both wheels no matter what (spooled locked when activated).
(We all know non-computerized abs/brake controlled open diff "4x4"s provide power to wheel with least amount of traction..)
I guess it depends on the situation and conditions.. you think you'll encounter.

Ice is the scary one.. I think studs or chains would be best then.. but someone with who deals with ice, especially on pavement... might know better..

[Silver350]

If the stock LS works, as it apparently does, just leave it until such a time that it doesn't anymore. By the time you wear it out you will know if you want
4WD. I went with a LS on my 2WD and would get a selectable locker next time.

What exactly do you mean by "winding up" the LS? I would have loved to see your van on two wheels like that, any better pics? I'm glad to know you were able to get out if that, it is one situation I'm not looking to get into.

[jage]

Originally Posted by Silver350

If the stock LS works, as it apparently does, just leave it until such a time that it doesn't anymore.

Doors deep in muck is not a good time to evaluate an upgrade!

What exactly do you mean by "winding up" the LS?

In that stance pictured there is no weight on the left front tire (looks like air in fact) and probably none or little on the right rear- the up on two wheels are probably catty corner. If that's the case, you're suppose to be able to apply brake pressure, thus trick the LS into powering the grounded rear tire to move the van forward.

It's never worked for me, and try as I might I cannot ever definitively say that my Jeep has LS (it does I just can't tell), I have no idea if my van might, so I understand it in theory, but in practice I'm a big fan of lockers.

[Nomadcat]

I had the Eaton Truetrac put into my rear and an E-Locker in the front. I have a Quadvan.

Putting in the Truetrac involved swapping out the axle - I believe you need a 35 spline job to go back there - but it was an upgrade in this case as I got a full floater. Yes, it was a used, refurb full floater from a Harley Davidson F-350, but it only had 12,000 miles on it.

So far - 30,000 miles in - I love it, but I haven't given it anything too gnarly to handle.

[louie]

Wow this is exactly the thread I've been looking for. I have a dodge extended van and have discovered if I want a rear selectable locker like an ARB I will need an axle swap. Apparently, there is no electronic/air locker for the Chrysler 9.25 axle. Will swapping out the factory axle with a dana70 effect van sway or braking ability?
Thanks

[coyotearms]

Wow! There sure have been a wild number of different combinations of "traction improving" mods used by folks responding to my initial questions. It has got me thinking now of what are the pros and cons of TrueTrac vs Detroit Locker if used in the rear, i.e. always at work compared to in the front of a 4x4 setup where you can choose to have it go to work or not depending on whether the hubs are engaged. I am particularly wondering about normal highway driving.

I've been told by a 4x4 shop that the Detroit Locker is always locked unless there is a speed differential between the wheels like when going around corners. This is fundamentally different from the TrueTrac which I have been lead to believe is more of a torque sensor it that if one wheel looses traction torque is transferred to the other wheel to a large extent. So when driving down the highway with patchy ice, I see the TrueTrac throwing torque to the wheel with traction, but what happens with the Detroit Locker? If only one wheel is on ice on a straight road, I seems that the wheel on ice would loose traction and spin up causing the Locker to disengage due to a speed difference. But then what happens to the torque on each wheel? Can anyone take a shot at that?

[Bones_GSXR]

I have True-Trac diffs front and rear. They do not pull one way or another when driving. I have driven 1200mi on winter Alaskan roadsat normal hwy speeds. I Plow with my Van anytime it Snows. I Travel anywhere Off Road that my Van Should be taken. TrueTrac's are not like a Limited slip. A Limited Slip trys to spin both wheels at the same speed while a TrueTrac sends the Torque to the wheel with the most traction. Watch the video on YouTube below and at the end they show the Torque splitting.
http://youtu.be/lZmsY2YvVsc

[coyotearms]

I believe you about the TrueTrac! It's the Detroit Locker that I can't quite get my head around on icy highway roads. The downside of the TrueTrac, as far as I know, it puts more torque on the wheel that can grab than a LSD, but not 100%. I think it is because of this folks may choose a Detroit Locker, not selectable, but truly locks.

[Silver350]

I've asked several places about a Detroit Locker and without fail was advised against it due to the vehicle spending so much time on pavement. Basically I was told that if the Oversteer it causes on icy roads doesn't scare the s*** out of me, the poping and grinding on dry pavement will drive me nuts.

You keep referring to a scenario where one wheel is on ice and the other has traction, but what about when 2 wheels are on ice with a differential that won't easily unlock? You will be facing backwards and in the ditch before your passengers stop screaming. Or possibly have turned your van into an SUV, a Stupid Upside down Vehicle.

On the other hand, if you have Advance Trac, the throdle will cut as soon as one or both wheels start spinning.