This is interesting....Locking rear axle also has limited slip?

[deeve]

I had read in some of the dozens of reviews of Ram trucks that ones equipped with a locking rear axle also acted as a limited slip when not locked. I dug around some and found one video or forum post that discussed that, but cannot find it now. Anyway, I thought I would test that our when my BH BC showed up with the locking rear axle. Having owned Wranglers with both anti slip and locking the concept of this was intriguing as it would be a cake and eat it too situation.

Fast forward to today when I found myself on a dirt road. With traction control off and in 2wd while flooring it I was able to get two distinct rear tire acceleration marks. I tried it a bunch of times with the same result each time. Each time there was not even without a hint of a emulated electronic limited slip function like Wranglers have using the ABS system. I forget the name of what Jeep calls that and I don't know if our Rams have it. Kinda assume we do as part of the traction control system. I looked particularly close for that as I think you cannot truly deactivate traction control. In my experience with the electronic limited slip there would be shading from side to side as the abs system modulated power. I did not see that.

I am no axle expert by any means, but take a look at the photos and let me know what you think. The road surface was a bit damp and had loose gravel on the shoulder and packed in the middle. I conducted the "test" with one wheel in the looser gravel and one on the packed as well as both on the packed. You can see the gravel is darker but that is because of the surface. Closer toward the middle of the road things were equal. Toward the end the right tire was marking more, but at that point I was in second gear and moving at a pretty good speed. Limited slip would act like that too, if I recall. This test is not as good as on ice or snow, but I think something more than an open differential is going on.

 

[Richard320]

I suspect the Electronic Stability Control is kicking in, It brakes the spinning wheel so the other side gets some torque.

 

[deeve]

That's what I thought, but from looking at it there is no shading or changes in the marks that I could see that would indicate electronics modulating the wheels.

On my Jeep it is appearnent something different was happening when electronics were acting as a limited slip. This, I didn't see it. I don't know...maybe things have gotten that good now. If that is the case that the electric traction controls is working that way, I do not see a need to choose limited slip over locker.

 

[Brutal_HO]

HD Power Wagon has locker/LSD. I think the LSD is gear driven vs the non locker LSD which is now a clutch type.

On the HD, you can also disable TCS to get the (clutch) LSD to kick quicker, gets the ABS nanny out of the picture.

 

[Dewey]

Good to know. I was a bit hesitant about the electronic differential especially after somebody awhile back mentioned only one wheel would be spinning when not activated.

 

[deeve]

HD Power Wagon has locker/LSD. I think the LSD is gear driven vs the non locker LSD which is now a clutch type.

On the HD, you can also disable TCS to get the LSD to kick quicker, gets the ABS nanny out of the picture.

That might have been what I saw. Kinda rings a bell. I wonder if we have a similar locker/lsd setup? I fully expected one wheel to spin or if electronic brake lock differential it to be similar to abs kicking on.

 

[Yankee Echo]

The electronic locking rear differential does not have mechanical limited slip built into it. You are witnessing the Brake Lock Differential (BLD) working as advertised. It's a good system for its intended use and responds very quickly.

From the owner's manual:
Traction Control System (TCS) - TCS monitors the amount of wheel spin of each of the driven wheels. If wheel spin is detected, the TCS may apply brake pressure to the spinning wheel(s) and/or reduce engine power to provide enhanced acceleration and stability. A feature of the TCS, Brake Limited Differential (BLD) functions similarly to a limited slip differential and controls the wheel spin across a driven axle. If one wheel on a driven axle is spinning faster than the other, the system will apply the brake of the spinning wheel. This will allow more engine torque to be applied to the wheel that is not spinning. BLD may remain enabled even if TCS and Electronic Stability Control (ESC) are in reduced modes.

 

[deeve]

Thanks. I'd say it works very well and better than my last gen wranglers did. I think that system with a locker is very good indeed.

 

[mikeru82]

My previous truck had the locker. I would often get a "one wheel peel" when the pavement was wet, especially if I was also turning. Pretty sure mine was an open diff when not locked. Doesn't really matter to me now since my truck has the anti-slip differential.

 

[deeve]

Looks like they don't do that anymore. Maybe it would be different if i tried it on pavement? Perhaps pretty low traction surfaces it works better?

 

[morrpar]

I thought I read somewhere that the two (electroinic locking and limited slip) can be combined in the same axle.
Here is a link :68261224AE - Water Pump - 2019 2020 Ram 1500 | Mopar Parts Canada

That of course does not mean that anyone has this installed in their truck.

When my truck comes in, (I ordered the e-locker) I will raise it on jackstands, rotate one tire and watch to see what the other rear tire does. This is an old-school method of verifying the presence of a limited slip.

 

[kapinallinen2]

I thought I read somewhere that the two (electroinic locking and limited slip) can be combined in the same axle.
Here is a link :68261224AE - Water Pump - 2019 2020 Ram 1500 | Mopar Parts Canada

That of course does not mean that anyone has this installed in their truck.

When my truck comes in, (I ordered the e-locker) I will raise it on jackstands, rotate one tire and watch to see what the other rear tire does. This is an old-school method of verifying the presence of a limited slip.

No limited slip with my e-locker.

 

[deeve]

I thought I read somewhere that the two (electroinic locking and limited slip) can be combined in the same axle.
Here is a link :68261224AE - Water Pump - 2019 2020 Ram 1500 | Mopar Parts Canada

That of course does not mean that anyone has this installed in their truck.

When my truck comes in, (I ordered the e-locker) I will raise it on jackstands, rotate one tire and watch to see what the other rear tire does. This is an old-school method of verifying the presence of a limited slip.

Hmm...I could try that. What will happen to the other wheel when you spin it?

EDIT..quick google search showed that if you spin one wheel one direction, the other wheel will go the same direction if it has limited slip. I tried it and the wheel did turn opposite direction which means for sure it is not limited slip. The BLD was doing a great job of imitating lsd. Would have been cool if it did though! Thanks for the education all.