Locker Options With Auto Transfer Case

[dezm]

Hey all, couldn't find any info pertaining to running a rear locker with the auto transfer case.

 

Does anybody have any experience running a rear ARB locker with the auto t case? I'm hoping it would work fine as long as you only activated it while in the 4H or 4L modes.

 

I'd love to just throw a Lokka on but that would definitely cause some issues with the auto mode while driving in slippery conditions on-road (a feature I use a lot in the winter here).

 

Are there any other drivetrain incompatibilities I might be missing? My engine bay badge says I have HG43 gearing, and it's an LSD.

 

Any insight would be appreciated! 

 

 

[PathyDude17]

I believe @fleurys had that auto mode t case and a rear locker? I know he’s done a lot of digging on the auto case and has f/r lockers, but can’t remember what case he has.

 

@R50JR has lokka and auto mode, but I don’t think he uses it as he lives in Arizona.

 

From what I know, you can lock both ends with the auto mode case, as long as you make proper adjustments / commit to certain scenarios.

 

if you’re in auto mode, never have the locker switched on.

 

if you’re not in auto mode, do whatever you want.

 

@RainGoat is heading towards this if I remember correctly, and should be able to contribute anything I missed or got wrong

 

It seems to me that the only issues can occur when you are in auto mode and turn on the locker, but I’ll defer to anyone who has actually tried that or can point to better info

 

there shouldn’t be any drivetrain incompatibilities in terms of gear ratio. I cannot, however, remember if the ARB requires an open carrier. Many (All?) auto lockers require open carriers to drop into.

Edited August 21, 2020 by PathyDude17

[Guest]

Not sure if an open carrier is required? As for having a locker with auto mode, I don’t see any issues even in 2wd as long as the ground is slippery enough to break traction. I’m trying to understand why having a locker in auto mode would cause any issues, especially with the rear. Auto mode doesn’t make the vehicle become full time AWD, it just gives power to the front when traction is poor which probably activated by the rear wheel speed sensors. Perhaps if you are locked you won’t have so much wheel slip and front will not engage while in auto. I don’t see that causing any or being an issue but may just have to adjust driving style. If [mention]Rockit [/mention] would ever make his badass truck known around here, he would have the answer as he’s dual locked. Anyone correct me if I’m wrong.

 

 

Sent from my Pathfinder

[XPLORx4]

Auto mode (AWD) simply allows the center differential to slip to compensate for different front and rear driveshaft speeds while turning. It normally biases output to the rear driveshaft, but can transfer up to 50% of torque to the front driveshaft if conditions warrant it. It doesn't know whether the front and/or rear axles are locked. In fact, you can have both front and rear locked while in AWD, and it'll work just fine.

 

Granted, if you're in a situation where you're using any kind of selectable locking differential, you'd best already be in 4H or 4L. Auto mode is for use while driving in inclement weather, not for off-roading where a locking diff is desirable.

 

Since the ARB is a selectable locker, it runs open when it's not engaged. Hence, it'll be invisible to the center diff while in Auto mode. By the way, the ARB locking diff bolts directly to the ring gear and fully replaces the carrier, so it doesn't matter whether you have an LSD or an open diff to start with.

 

The Lokka (front diff) is an automatic locker. Again, whether you're in 2H, 4H, 4L or AWD, it'll work the same. The AWD system won't even know it's there.

[RainGoat]

Auto mode (AWD) simply...

This is my general understanding & use. Currently, I have an ARB Front Locker & an LS rear differential repacked by[mention=36148]hawairish[/mention] sitting in my garage awaiting install - along with my @pinestospines 3”SFD. Since I’ll be finally increasing my tire size and I now use the truck as either a weekend toy or a hauler instead of an overlanding grand tourer, I’m planning to regear while I have those diffs open but I just haven’t gotten around to acquiring the gears yet. Realistically, this will probably get done with[mention=37543]towndawgr50[/mention] this winter.

 

[dezm]

Some great info here thanks guys! Sounds like this will hopefully be my next major upgrade. Time to start saving...

[hawairish]

Echoing what XPLORx4 said: there are no issues here.

 

We put front and rear ARBs in @Rockit's QX4 the other month, so he can back drivability claims.  Having them is inconsequential in Auto mode because they are disengaged.  Though if you're also planning to get a front ARB, just know that ARB introduced issues that the previous locker did not have (I've installed both).  The newer style requires pulling the pinion gear from the case, grinding it down 1-2mm on the head, and modifying the oil seal ring on the RH stub shaft, which requires a press to remove and reinstall in a new position a few mm's off.  Lousy design on ARB's part.

[dezm]

1 hour ago, hawairish said:

Echoing what XPLORx4 said: there are no issues here.

 

We put front and rear ARBs in @Rockit's QX4 the other month, so he can back drivability claims.  Having them is inconsequential in Auto mode because they are disengaged.  Though if you're also planning to get a front ARB, just know that ARB introduced issues that the previous locker did not have (I've installed both).  The newer style requires pulling the pinion gear from the case, grinding it down 1-2mm on the head, and modifying the oil seal ring on the RH stub shaft, which requires a press to remove and reinstall in a new position a few mm's off.  Lousy design on ARB's part.

Good to know! So far only planning on the rear so hopefully should be a straight forward install when the time comes.