Locking differential

[62Blazer]

To answer the original question.....yes, you can run a Detroit locker in the front. Even without any type of locking hubs or front axle disconnect you would not notice it when in 2wd. The design of the Detroit locks together based on torque input from the driveshaft (which comes from the transfer case). With no torque input it basically freewheels, which is the same concept that it uses in operation when you coast it will unlock. Most automatic locking differentials work the same way (Detroit, "lunch box" lockers, Grizzly locker, etc...). I've personally ran one in a front axle for at least 15 years and you do not notice it all while in 2wd on a truck with drive flanges (i.e. no locking hubs or disconnect).
The only thing I will say is that it doesn't work very good if you just want to run 4wd on snowy roads at higher speeds, like if you are driving to work and it's snowing out. But otherwise it works good off-road or other times you need the traction. I think a front locker makes more of a difference than a rear locker in many conditions, especially with a heavy diesel up front.

A limited slip is not as effective as a locker in extreme situations. In wet grass or shallow and even mud a limited slip can keep both tires spinning, but get the vehicle really crossed up or one side down in a deep rut and you will find the limitations of a limited slip very quick. Also for those people saying just dragging the brakes makes an open diff work like a locker.........yeah right! It can "help" a little but get in a tough spot and you can apply all the brake pressure you want and it won't help. If you could apply brake pressure separately left or right, like cutting brakes on a buggy or tractor, it would be better but you can't on a normal vehicle. Same thing with traction control and other electronic systems. Yes, they "help" but they are not the same in extreme situations. The biggest problems is they wait until the tires are spinning and the vehicle is already basically stopped before working.

Also get a kick out of people arguing about the exact definition of limited slip, clutch packs, torsen diffs, yada, yada.... everybody knows what the original poster is talking about.

 

[lpennock]

So you had the manual locking hubs?

I’m wondering if it would effectively work the same with the front axle disconnect but w/o manual locking hubs. I don’t see why it wouldn’t.

It would work but you would most likely not like it. Here is why.

1. Your front drive shall will spin all the time. The axle disconnect keeps the drive shaft from spinning by counter rotation of the spider gears so force is not transferred to the ring gears. The Detroit will not allow counter rotation and will transfer the drive to the drive shift.
2. You will have a steering pull as the driver side will see the load of the Detroit and drive shift that the passenger side doesn't see.

If you want a Detroit up front you are better off defeating the CAD and keeping both axles always locked together. A Detroit that isn't being powered drives fine other you will notice a slight tendency for the steering wheel to go back to straight quicker.

Also remember that once the drive shift is spinning full time, the double cardin centering yoke needs greasing every 7500 miles or sooner. With the CAD it isn't critical to follow the service interval. If you don't keep it greased it can seize and peal the side out of the transfer case.

 

[62Blazer]

If the truck is in 2wd (i.e. no power coming from the driveshaft) the Detroit is by default "unlocked" between the two sides. I have not personally had a vehicle with a front Detroit and CAD system, but had a buddy you had a Jeep Wrangler that had CAD and a front Detroit and he drove all the time for years (drove it to and from the trails). He stated the front Detroit was not noticeable at all in 2wd. I would like to confirm how a Detroit would behave in regards to spinning the front driveshaft, but wouldn't think it would be any different than an open diff in 2wd with the CAD???? If I get motivated maybe will jack up the front end of my rig and see what it does.
Going to guess there simply are not many, if any, people on this page with a front Detroit locker in this type of rig.

 

[man n black]

2018 2500 Mega Cab Laramie 4x4 with the 6.7cummins.

Sooo I’m wanting to up the off road capabilities of my truck. Looking to add a locking diff. Rear diff in mine I believe is the helical anti-spin(LSD). Front is open. My truck is also equipped with the front axle disconnect so the front drive shaft does not spin unless 4x4 is engaged.

I know a Jeep Cherokee guy who runs a front Detroit locking diff. But he also has manual locking hubs. So with hubs unlocked it drives normal on the street. Hubs locked when off road then it’s like a typical Detroit style locker. Could anyone advise me if a similar setup would be possible in my truck? Because it has the axle disconnect for when it’s in 2wd seems like it might be possible to run a front locker like this and still drive normal on road.

Not looking to debate pros/cons of front vs. rear locker.

TIA.

The power wagon e lockers would be a much better bet.

Front lockers really suck in my experience, an old 70's chevrolet with manual hubs. It had super swampers and it was very difficult to drive in four wheel drive. Don't remember it affecting anything in 2 wheel drive.

Just sharing my experience here on a 2500 Cummins CrewCab.

We replaced everything in the front diff a few years ago when we had a front pinion froze after some shop work. I looked at every option out there for our trucks.

The OEM rear locking (torsen) diff has a poor lockup ratio. Going aftermarket torsen will greatly improve this with quicker rear diff locking and much better offroad performace than OEM. You would still have to ride the brake pedal to intentionally lock.

The OEM elockers from the Power Wagon are an awesome and viable option, but they are crazy expensive and not a bolt in replacement. They require a fair amount of modification to your existing differentials to make work reliably / correctly.

I would recommend going with the AirLocker in the front diff. This is what I did in addition to other upgrades while I was in there. The Airlocker is a largely bolt in / out affair, you get the air compressor which (if you get the outlet kit) makes for some nice other capabilities should you find yourself needing to pump up trailer tires or floaties at the lake, and should you ever need or want to go full locked route you can always add a rear Airlocker fairly easily.

Our "auto" 4WD system works just like OEM in snow and at higher speeds with the Airlocker turned off as you retain the OEM vacuum operated setup; but when its turned on it works a charm....far better than OEM, but of course the truck will absolutely want to go whichever way the wheels are pointed when the diff is locked.

Ch

 

[lpennock]

If the truck is in 2wd (i.e. no power coming from the driveshaft) the Detroit is by default "unlocked" between the two sides. I have not personally had a vehicle with a front Detroit and CAD system, but had a buddy you had a Jeep Wrangler that had CAD and a front Detroit and he drove all the time for years (drove it to and from the trails). He stated the front Detroit was not noticeable at all in 2wd. I would like to confirm how a Detroit would behave in regards to spinning the front driveshaft, but wouldn't think it would be any different than an open diff in 2wd with the CAD???? If I get motivated maybe will jack up the front end of my rig and see what it does.
Going to guess there simply are not many, if any, people on this page with a front Detroit locker in this type of rig.

Actually a Detroit is a normally locked differential. Since there is no forces on the CAD side it will stay locked and drive the drive shaft. There has to be a force differential to cause one side to unlock. The CAD will appear as a wheel in the air.

 

[62Blazer]

Actually a Detroit is a normally locked differential. Since there is no forces on the CAD side it will stay locked and drive the drive shaft. There has to be a force differential to cause one side to unlock. The CAD will appear as a wheel in the air.

You really have me curious now and will have to do some more research on this. I do know that the only way a Detroit will unlock is if you get off the gas and are coasting. Turn all you want, but if you are applying power/throttle to the vehicle it will not unlock in a turn and will only unlock if there is no torque going to it. Guess that was what I was thinking about.
Still really don't think it would cause any issues with a CAD when in 2wd but again do not have personal experience with that. If I get a chance will check with a buddy who does have experience and see what he says about the front driveshaft spinning. He is also a long-time mechanic and off-road vehicle builder so have good technical knowledge.
I have personally owned multiple vehicles with selectable front lockers (open or fully locked), "automatic" full-time lockers like a Detroit, and an rather aggressive aftermarket clutch type limited slip front. The limited slip was least favorite overall. Obviously had it's limitations off-road and often got in situations where only 1 tire would spin, but it also had poor handling characteristics on snowy or icy roads. When turning on a slick road in 4wd it would always want to push the vehicle straight versus turning almost as bad as a full locker, and was like this whether on the gas or coasting. At least with a full locker if you let off the throttle it would tend to unlock. You could also feel the limited slip even in 2wd if the hubs were locked in.
Have also been on the trail watching many newer vehicles with the standard electronic traction control. Have to admit at being rather impressed the first time I saw a newer Jeep Wrangler with traction control work on the trail as it was much better than just standard open diffs, but still didn't work as well as a locker. Though keep in mind that certain vehicles, such as Wranglers meant to go off-road, have a more "aggressive" traction control setup than the typical car.

 

[lpennock]

I had front and rear Detroit soft lockers in my Jeep Cherokee. I didn't have the CAD axles and I didn't realize how much the front Detroit affected the steering until I put on front locking hubs. While it wasn't bad to drive without the hubs it did make the turning a bit heavier, especially in highway lane changes as there wasn't enough speed difference to over drive the slower turning wheel and cause it to unlock. In turns you really didn't notice it as the speed difference between the wheels was enough to cause the unlock to happen. Under power, as you said, it was very hard to get enough torque difference before tire slippage to cause it to unlock but with proper feathering of the power it was possible.

From Detroit-Locker-FAQ
The Detroit Locker is an automatic locking differential. This means it is normally locked during straight-line driving and sends 100% of the available torque to both wheels equally. During turns and maneuvers, the internal components unlock to allow one wheel to spin faster or slower as necessary (free wheel). When the vehicle returns to straight-line driving, the components re-engage and provide equal power to both wheels.

The good news is a vehicle with F&R Detroits is virtually unstoppable. The bad news is that on Snow and Ice they are virtually unstoppable and unturnable.