Rubicon 4x4 & lockers: how do they work?

[eddified]

I have a question about how Jeep's Rubicon 4x4 works. I know that many 4x4 systems are quite different. For example, my understanding of how the 4xe Sahara 4x4's Selec-Trac system is as follows (please correct me if wrong): there is no center diff, instead there is a clutch pack which can be 100% disengaged for 2 wheel drive on-road, or 100% engaged for 4wd (when engaged, it's functionally similar to a locked center diff). But there is no center diff at all, right? (Info curtesy of wikipedia: https://en.wikipedia.org/wiki/Jeep_four-wheel-drive_systems#Selec-Trac_II )

For the latest Rubicon models: how does the Rock-trac system work? The wikipedia link above doesn't really say much about how it works. Does it have a center diff? Does it come with lockers for a center and rear diff then? And if there is a center diff, does that mean that when 4x4 is not engaged (on-road driving in good conditions) that it is functionally an all-wheel drive, not 2wd? Sorry if these are dumb questions.

Sponsored

 

[Kurlon]

The Rubicon 'rock trac' is just like a regular Wrangler transfer case, no center diff, no clutch packs, but 4L is 4:1 reduction instead of 2:1.

 

[DewHawk]

Check this out:

 

[eddified]

Check this out:

Thank you, I did see this video, but it is lacking in detail.

 

[Digger 5]

The Rubicon 'rock trac' is just like a regular Wrangler transfer case, no center diff, no clutch packs, but 4L is 4:1 reduction instead of 2:1.

FYI- The regular Wrangler t-case is 2.72-1 reduction.

 

[Badweissenbier]

With the rubicon you can now get the select trac system. I’m sure they just put a clutch system in the t case for auto engagement. It stays 4:1 for low range just has an extra position for auto engagement.
Someone in the know may have more but it’s a 4wd not an awd so it won’t have a center differential.

 

[Chocolate Thunder]

You’re asking different but related question. First, the Rubicon with RockTrack has front axle and rear axle lockers. When in 4WD LO range, you can lock the rear axle only or both the front + rear axles. What this does is lock the left and right side of the affected axle together so that if one side loses traction but the other side has traction, the axle can still grip because the side with traction is still being driven. Helps stop slipping that would occur if they’re not locked.

Your other question is about a center differential. This is actually the transfer case. That’s what engages 4WD when you select it. When not engaged, the Rubicon operates in 2WD, not AWD because the front wheels are only driven when it’s locked in 4WD HI or 4WD LO.

 

[Kurlon]

FYI- The regular Wrangler t-case is 2.72-1 reduction.

Yup, my mistake there.

 

[DewHawk]

Your other question is about a center differential. This is actually the transfer case. That’s what engages 4WD when you select it. When not engaged, the Rubicon operates in 2WD, not AWD because the front wheels are only driven when it’s locked in 4WD HI or 4WD LO.

There is another consideration to take into account; the Rock Trac Full Time 5 position Transfer Case. This is a specific transfer case that also includes 4Hi Auto and acts like an AWD system for day to day use and intermittent grip loss (semi slick road surfaces). It differs from the Rock Trac Part Time system that is 4 position (no auto function). 4Hi Auto is unique in that it uses a viscous clutch type engagement to apply power to the front when needed.
Decent demonstration here to see how it works:

Sponsored