Tow Rig/Overland Differential Choice? - Torsen, Gov-Lock, Clutch, etc.

Vehicle in question is my 2004 Suburban 2500. It's an 8.1, so it has the 10.5" full floater rear end with tons of options out there from the aftermarket. Currently an open diff.

Lately, in addition to being a tow rig, the Suburban has become something of an overland vehicle. Rally has taken me to a lot of out of the way places with challenging access, and I've now had a few iffy situations where some form of traction assist nearly became critical because either one wheel at each end was basically off the ground, or one side of the vehicle was going through mud and just wanted to spin the muddy side's tires. Sand has also been interesting a few times, and I basically got lucky making it through.

If you all were picking a differential for something like this that's never going to be a hard core rock crawler, what would tickle your fancy?

My thoughts below...but I have no firsthand experience to go off of. Any glaring gaps?

• Open diff. I have it, it's mostly fine, but it's almost been not fine enough that I feel I need to do something about it.
• Clutch plate diff. Seems like, to work off road, you'd need a ton of plate preload, and my Ford buddies with the factory LSDs say they may as well be open diffs off road. So I don't think this is what I want.
• torsen/Tru-Trac diff. 3.5x torque bias of the spinning wheel if my research is correct. I've been told these work better in lighter vehicles, but no idea if that's actually true. Doesn't seem like it would do much with a wheel in the air or a wheel with nearly zero grip, like ice, wet grass, or mud. but zero maintenance, smooth operation, etc. is all very tempting.
• Gov-Lock. Factory locker for this truck. Cheap. Requires a 100 rpm speed difference between wheels before locking, at which point it is fully locked, on or off. Only works up to 20 mph wheel speed. Reputation for exploding. I like the idea of these... I don't like the exploding part, or the 20 mph speed based on the sand and mud situations. Allegedly can be modified to get rid of the locking speed limit and reduce the wheel speed differential before locking.
• Detroit or other ratcheting locker. I don't even want to consider these for the street manners. Same for a spool.
• E or air locker - seems like a lot of work to install, plus manual driver intervention, but otherwise foolproof. I don't have onboard air. Yet.

I'm mostly between the Torsen and a Gov-Lock, with or without modifications. Anyone here have experience with the Tru-Trac off road?

Passenger front is up on a rock in the pic so it's flexed a bit, lots of this stuff that's easy in the dry but quickly causes problems if there's surprise rain or something.

I'm big fan of trutracs in street-driven vehicles. Had one in my 3rd 4runner, seamless under normal driving but always there with extra traction when you needed it. I think it's a huge benefit over an open/locker combo as it's there transferring torque in all the situations you'd normally just spin the inside rear tire. 

I never did much technical offroading with it, just lots of exploring through CO and UT. I know it will act like an open diff when you fully lift a wheel, but I never had a problem with the types of roads you'd run into "overlanding".

I've also experienced torque biasing diffs in an NA miata and E46 street/track car. I like them so much that I factor in trutrac (or similar) availability into my purchasing decisions. I replaced the 4runner w/ a 3rd gen tacoma, which has the open/E Locker combo, given the option I'd happily swap it out for a torsen. 

A locker is better for the really technical offroading, when you're fully unloading a corner, but provides no benefit the rest of the time, where a torsen is the opposite. It really comes down to priorities.

Question, if you lift a wheel with a torsen and apply the brakes and gas at the same time, does that alleviate the issue?

Lifted, the spinning wheel has 0 torque.  So 0 x 3.5 = 0.

But say you give it resistance with brake torque of 5 units.  Now lifted wheel torque = 5  Opposite wheel torque is 3.5 x 5 = 17.5.  Minus the 5 units of brake torque = 12.5 units to drive forward.

I've only had torsens in autox / performance cars and their street manners are pretty great.

I don't have the answer myself, but I'm curious to hear what the hive comes up with.

My use case for my recently acquired Land Cruiser is similar to yours (excluding the towing.) I have open diffs at the moment and have wondered about what might work best for me. Based on my past experience with 2WD cars that I used for everything from street driving to rallycross to exploring as far/deep as I could on primitive roads, a clutch type LSD makes a big difference. This left me puzzled when looking at the ih8mud forums about differentials;  see a lot of advice suggesting that clutch-type LSDs are 'garbage' and 'a complete waste of money.' I even found a few folks suggesting that one might be better off with open diffs. There were several suggestions to just jump straight to onboard air with lockers. I'm guessing (but I'm not completely sure) that this might have to do with the fact that there are lots of ambitious and intense 4-wheeling types on there, who are seeking out very technical trails, frequently crawling, getting wheels in the air, etc.

My style is more just having extra capability for overhead for when the road gets rough and it just dumped rain, or for the occasional road washout or creek to ford and the like.

Torsen can work okay if you have lots of flexibility.  Like Jeep or Land Rover levels of articulation.  Or if you have a sophisticated traction control system OE.  In your case, I'd recommend a selectable locker.

In reply to TravisTheHuman :

Yes, but it works best if you can selectively apply the brakes.  Otherwise you're fighting with yourself to keep up momentum.

Well, if you can selectively apply the brakes, you can do a lot more with an open diff also :)

Clutch pack in the back, Torsen in the front   

One thing to keep in mind about the G80 aka Gov-lock is that it's still a clutch type LSD. It's fully open until the wheel speed differential reaches its limit, then it kicks in as a typical clutch LSD. At least that's how they work in the 1500s with the 10 bolt. They're notorious for being completely worn out (clutch plates) by the time you reach 100k miles. 

Did these axles ever come with factory e-lockers in newer trucks? I'm going through this thought process with my Econoline ambulance camper and the cheapest option is to buy a new OEM Ford e-locker for $600. Aftermarket is all $1200+. All it needs is power and ground to activate so there's a little bit of wiring involved but still very easy. 
 

Re the amount of work involved; Any of the options where you have to swap the carrier will be about the same amount of work. I've installed probably 30 ARB lockers at work, and those are more work with wiring up the compressor, locker solenoid, wiring, air lines etc. But as far as the differential install they should all be the same. Pull the carrier, swap the ring gear to the new carrier, set backlash and reinstall. 

The considerations of an overlanding Suburban are way different than for a rock crawling Wrangler. The dimensions of the Suburban are going to limit how much trouble you can get into in the first place.

If the type of obstacle you list in your picture is going to be typical of what you're going to be encountering, or you're dealing with slightly deep mud or sugar sand, the Gov lock for the rear will make a pretty big difference from what you have now. They have a reputation for exploding because people love to do smoky burnouts with them and repeatedly drop the clutch or do neutral drops and shock the hell out of them. If you're just looking to increase traction at low speeds, it should work just great. It's also probably the easiest one to procure and install, since it came from the factory. 

I'd start with the G80, and if you find out you need more, you can always go deeper down the rabbit hole. However, if having  a G80 in the rear and using your brakes to shift torque around doesn't work and you find you need more, I'd say at that point you put an e-locker in *front*.  That way it is 100% off until you need it, so it won't mess with how your steering end behaves unless you push the button.
 

Thanks for all the input.

• the "brake to bias the torsen" probably does work, at least to some degree. My google rabbit hole suggested that they work better in the front because most production trucks have a lot more front bias than rear. With a rear torsen, it takes so much brake pressure that you've now stopped the vehicle with the front brakes before you've transferred enough at the rear to get going. About half the videos I've found showing operation seem to show some struggles with this when wheels are off the ground. The Suburban also seems to cut throttle if you're on the brake at the same time, which doesn't help. Seems like the e-brake might work though, if it's a really strong e-brake.
• I don't have a ton of articulation, not that I have much frame of reference besides my K1500 Silverado. IFS front, stiff 3/4 ton springs. I've got a bit of a "mid-travel" shock setup on it so I've got about a foot of total travel at each wheel, it just doesn't flex much before a wheel leaves the ground.
• No selective brake application on GMT800s. While there was traction control available, it's all throttle-based. If it had that feature I think the Torsen would probably be a great fit.
• I didn't realize the Gov Lock was a clutch type diff. All the youtube videos seem to show basically a full lock after they slam into that locked mode.
• No factory e lockers on the GM stuff. No one offers one for the 14FF 10.5 rear end either, as far as I've seen. Good point that the marginal difficulty of installing a selectable locker is small, but I'm not sure I want to deal with air for the ARB option.

More googling also seems to suggest the gov lock isn't known for being weak on the bigger axles. Seems like it may be a decent option for what I'm doing, without the potential challenges of getting a torsen to transfer enough torque to move a 7500 lb truck.

I think a look towards what Toyota sells kinda send the message for function and reliability.

Toyota only offers a rear locker on their modern 4WDs. which I think helps point you even further to that direction.

so I would look at an electronic or air rear locker, and maybe the torsen up front if you still want something extra up there, but I question if it's needed.

I am a big fan of the selectable locker. Perfect road manners and the absolute best traction off road. They aren't "that" hard to install compared to any other diff you'd be installing. As far as driver intervention, flipping a switch when you leave pavement isn't too bad. I've had one for a little over a year in my JT and I'm a big fan.

Air lockers are great if money is no object. Torsens are a good mild option for front axles but maybe too mild for the rear. A Detroit locker can be a good option if it's not too aggressive, but if it's locking up on the street it will eat your tires alive and generally become a PITA. Clutch-type diffs tend to end up either working like a torsen or a welded diff offroad depending on how you set them.

I'd look for a G80 rear. They are much better than an LSD in that they achieve full lockup. I have one in my Suburban and at 340k it still works perfectly. The locker in my son's Suburban also works perfectly. 

I ran a Torsen in the front of my XJ. It worked very well but did make the steering a little heavier on the highway. 

I don't recommend a lunch box locker like the Spartan or Lockrite. I've used both. One in the Samurai, one in the XJ. They work fine off road but for street driving the bangs and pops get old. 

In the same line of options, my F250 2wd (V10) has an open 3.73, in a Sterling 10.5. The V10 trucks actually get better mpg on the road with a 4:30 - at the moment I just put very heavy duty LT225/75R16 on her (effective ratio 3.99!) it a start!

When I do change rear ratio, what LSD/Lockers are available, for the Sterling?

No intentionally off reading, but most campgrounds, and my hilly driveway, can be a bit "primitive"

ABSOLUTELY CAN NOT afford E or air selectable, so no need to suggest... wish I could.   
Had a Detroit Locker, stock in the 72 IH Travelall I had for a bit - no clue how it was set up. Only time I even realized it had it, was the clicking in low speed traffic on a curvy road, with windows down. 
If too far off topic, I will start a fresh one. 
 

In reply to 03Panther :

Like the 14 bolt, the Sterling 10.25/10.5 is widely supported by the aftermarket. A new OEM ford e-locker is only $600. It's definitely one of the cheaper options for that truck. Cheaper than a Detroit. If you want to change gear ratios, buy a junkyard axle with a factory locker and the gear ratio you want. You'll be way ahead of regearing and installing something yourself. 

In reply to WillG80 :

2 summers ago, I drove a friend of mine out 2hrs, to buy a parts truck for $500, cause the yards around here (and most sale ads) want $1200 -1800 for a 99 up rear end. And won't let you go look at the tag before you buy it, and they go pull it out. 
We drove the truck onto the trailer! No doors, fenders, or bed. 
turned out to be a 4:30, open. Replaced his 3:73 limited slip that needed clutches. Sold that with the truck, later! So I have a bare housing/axles, and another parts truck with a complete axle, also open, 3:73. 
Unless I find a GRM Relay from a decent yard, or pick one up in a town I'm work in/passin' through, I'll have to stick with new parts. 
But I can save enough pennies for a $600 e locker! What years would that have come in? Thanks. 

I know im not answering the question, but if the locker is intended for the rare "in case of emergency " situation where you get into something a bit too challenging, would a winch be an option?

Front mount receiver and a receiver mounting bracket could enable you to pull yourself forward or back to get yourself out of a bad situation without affecting the driving characteristics. 
 

I put a Tru-trac in my F-250 and loved it, but it really sounds like you want a locking limited slip if you're looking for serious one-wheel-in-the-air off-roading. 
 

I put a ratcheting locker in my Trooper and while it's exceptional off road, it's miserable on the street. I wouldn't do it in your situation. 
https://auburngeardiffs.com/select-a-loc-ltd-slip-to-lock/

In reply to WillG80 :

A Quick Look up (did not know the factory had put them in) answered that question. But same quick lookup, is finding just the locker, for 800 - 1100... or backordered, indefinitely. 
So that might not work out. 

In reply to No Time :

Actually, it's a great answer.   I have one in my F350 FX4, even though it's on stock rims, mild ATs, and no lift. 
But, it's not highway worthy atm. 
I've taken it places in the woods around my property, pushing down trees  and brush to keep the land walkable for the owner/neighbor. Never used the winch, except to pull stuff up onto my deck over trailer! It's a beast in 4low. Places I would never take my 2wd!

In reply to Tom Suddard :

Not sure if that was for the op, me, or our friends following along!

I hope I'm not highjacking the op!

The 03 F350 FX4 has whatever LSD the factory used, and even with the factory 3:73, it will go anywhere I need, and has great road manners (when it's road worthy) it's stuck in 4low atm, but since it's not tagged / insured, it can't leave the property, so I'm just using it as a tractor right now. I have no clue if the LSD is adjusted right, or working correctly, but it's low miles (at 155K) so I assume it is. Only 4wd I've really driven that much, through all my years. 
My interim tow pig ended up being a V10 2wd, 3:73 open, and will slip a tire, pulling a 8' trailer around in the gravel driveway! Just a minor slip ... not worried about getting stuck - just don't like the divots in my gravel!

And can see it being an issue in the sugar sand in some of the FL campgrounds 
 

In reply to WillG80 :

I did find some links on sites discussing those for reasonable prices. In 2019. Links now are dead, or go to current Ford price of $1048.95. Plus shipping 

Thought I found a Detroit for $800 on one of those links. But they slipped in a Dana 60 on me