Searched the interwebs and this forum but can't find an answer.

Is it possible to add a helical (e.g., Torsen) limited slip differential to the 10.5" Sterling or M275 rear ends? Retaining the factory electronic locker is strongly desirable but not absolutely mandatory.

There are a few DIYs online of people rebuilding the 10.5" Sterling with the "Traction-Lok", clutch pack based LSD but I don't want to deal with clutches and the inevitable performance decline over time.

As much as I'd like to think otherwise, most of my driving is on pavement and for my use cases, the LSD is better than the locker.

There is only 1 HD truck w/ a factory equipped limited slip *and* locking diff (Ram PowerWagon) but I don't want that truck.

 

I am confused by your statement:

As much as I'd like to think otherwise, most of my driving is on pavement and for my use cases, the LSD is better than the locker.


I thought the E-Locker was a LSD unless it was switched to the Locked state. How is the LSD better?

Thanks,
Dave

 

I'm under the impression that the factory e-locker, when unlocked, behaves as an open diff with "electronic limited slip" (i.e., stability control applies brakes to the spinning wheel).

If accurate, this is materially worse than a mechanical LSD because the brake application causes the exact opposite of what you're trying to do (accelerate).

While yes, applying a brake to 1 wheel is better than spinning it uselessly, it doesn't compare to the more effective torque redistribution that a true, mechanical LSD can do.

This begs the bigger question: does the factory e-locker have a mechanical LSD built in already?

 

If I am ready your question correct. The E locker is a locked diff when turned on similar idea to an air locker, and an open diff when turned off. No in-between like a limited slip.

 

The factory locker is a locker only. Meaning it locks both wheels together to turn st the same speed no matter terrain, if turning, one wheel in the air, or whatever. Both wheels turn at the same speed. No LSD function. Should only be used offroad in slippery conditions or you could break axles halts. The factory locker is basically a spool when locked and open when unlocked and is user selectable. There are auto lockers which function in a ratcheting type way but they aren't very smooth on the road and can have odd handling characteristics.

A open diff allows wheels to turn at different speeds such as when turning. Great for road use as there is never any binding. However, power goes to the route of least resistance, meaning the tire with less traction. In other words, you could have one tire on dry pavement and the other in mud or ice and potentially be stuck. Modern traction control applies brake to specific wheels in an attempt to keep all wheels turning at the same speed, effectively slowing the spinning wheel and putting power to the wheel with traction.

A limited slip, either helical or clutch type, mechanically attempt to put power to both wheels equally yet still will allow some differential in speed for corners.

In other words, the factory locker is great in some conditions but is worthless in day to day use on slick roads. This is where a limited slip would shine and why someone may want a LSD instead of a locker.

To the OP, sorry I don't know if any are available at this time but would imagine at some point they would be.

 

Well stated.

Thanks for the info - I may be guinea pig on this one

 

Thanks for the clarification.

So in a nut shell the e-locker would be used similar to the 4X4 function, on slippery surfaces only. The e-locker will not bind or break apart unless engaged on dry surfaces, but will provide the best traction on slippery surfaces in 4 wheel with all 4 wheels providing traction.

The electronic locker on the SD's I am assuming means that the operator engages the system manually via a switch, not the computer engaging the system as it sees fit.


Thanks again.

 

I had terrible luck with the helical LSD in ram trucks. Enough to switch to Ford because of it.

 

Yes it is engaged with a switch but the computer will turn it off above a certain speed. I can not remember the exact speed so I might be wrong here I think it 30Km/h or 20MPH.

 

What happened?

I was under the impression that helical LSDs were pretty bulletproof because they don't have clutch plates to wear out.

 

For anyone else interested, I found a product that might do the trick (assuming they make a fitment for the Sterling and/or M275): Auburn ECTED

Leading Manufacturer of Traction Enchancing Differentials & Planetary Drives - Auburn Gear

Unfortunately, there are a couple of things I cannot live with on the ECTED:

1) It is clutch pack based
2) It is *NOT* user serviceable when the clutches wear out

 

Something to note. The Ford selectable locker is rear axle only. The front is still an open diff. You control it. It should only be used when traction is very limited.

As to clutch type limited slips, don't be so quick to write them off. Yes they can wear out but it takes a long time under normal conditions. If you're constantly hammering on it trying to spin tires or offloading it'll be quicker but it normal use you could easily go 100k before it's an issue. I understand where you're coming from but in a truck I don't see it being an issue. Even when it does, Auburn is a good company that has been around for a long time and has a decent reputation.

 

The eaton truetrac is a great rear diff for the Sterling. It is a helical gear LSD that locks up super quick. In daily driving you will not know it is there except you wont have the "one wheel peel" like you would with an open diff or the ford e-locker when it is not locked. I put one in my 06 Powerstroke with an Eaton e-locker in the front axle. Perfect combo in my opinion.

My 2016 has the rear Ford e-locker and of course an open diff in the front. With the torque of 6.7 I wish I had a Truetrac in the rear instead of the e-locker as it is very easy to break loose one rear tire in wet weather, when there is a little gravel or sand on the road, etc.

 

Yup, the Truetrac is a great unit. Is it available for these axles?

 

I had one go out in a 2013 Ram 2500 with the 5.7 hemi. Truck had 60k on it and never pulled a trailer. It was driven by an employee. On my personal 2014 Ram 3500 dually it would chatter real bad in reverse, or turning a corner under load. Kinda like diving a square wheeled wagon. Only way to fix it was new gear oil, it would help for about 5k miles before it returned. Chyrsler refused to warranty it despite 3 trips to dealer. After a heater argument with service advisor for telling me it was fine, I said screw it and bought a Ford.