Selec-Trac full time 4x4 4WD system discussions

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The Great Grape Ape

The Great Grape Ape

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Additionally a little tidbit of insight from Jalopnik’s David Tracy who was a design engineer during the JL development, when he talks about the CV joints;

But I learned that those only come on Wrangler Saharas equipped with the optional full-time transfer case (which exists, in part, to pass a stringent Euro NCAP brake test that a part-time system would struggle with).

https://jalopnik.com/the-2018-jeep-wrangler-didnt-get-soft-it-got-much-bett-1821160227

Interesting, did not know about that.
Sadly, none of these new reviews seem to actually test braking.





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Jeepsterfreak

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Additionally a little tidbit of insight from Jalopnik’s David Tracy who was a design engineer during the JL development, when he talks about the CV joints;

But I learned that those only come on Wrangler Saharas equipped with the optional full-time transfer case (which exists, in part, to pass a stringent Euro NCAP brake test that a part-time system would struggle with).

https://jalopnik.com/the-2018-jeep-wrangler-didnt-get-soft-it-got-much-bett-1821160227

Interesting, did not know about that.
Sadly, none of these new reviews seem to actually test braking.
Do you know about the return of Front Axle Disconnect as reported by fourwheeler review? This is the first I've heard of its return.

http://www.fourwheeler.com/news/1711-first-look-2018-jeep-wrangler-rubicon/

"Sadly, front-axle disconnect (FAD) returns to help boost fuel-economy, albeit in a more durable electric form, not the troublesome vacuum system of the past. Thankfully, Jeep engineers have JL owners intent on replacing their front axle covered with a software workaround that allows the FAD to be disabled by the dealer. These same dealer tools can also reprogram popular parameter changes required by enthusiasts, such as gear ratios and tire size."
 
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The Great Grape Ape

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Do you know about the return of Front Axle Disconnect as reported by fourwheeler review? This is the first I've heard of its return.

http://www.fourwheeler.com/news/1711-first-look-2018-jeep-wrangler-rubicon/

"Sadly, front-axle disconnect (FAD) returns to help boost fuel-economy, albeit in a more durable electric form, not the troublesome vacuum system of the past. Thankfully, Jeep engineers have JL owners intent on replacing their front axle covered with a software workaround that allows the FAD to be disabled by the dealer. These same dealer tools can also reprogram popular parameter changes required by enthusiasts, such as gear ratios and tire size."
Yeah, actually in the Jalopnik review he mentions it, and also mentions it’s not the bad option that people associate with the JL, but he also mentions that the nice thing is that it can also be replaced as well.

Still others will question the front axle disconnect, which allows the Jeep to drive in two-wheel drive mode without spinning the front driveshaft unnecessarily—a fuel economy enabler. A similar device that used a fork to mechanically join two sections of a halfshaft via a sleeve also existed on old Jeep vehicles like the Wrangler YJ of the late 1980s, though it is not remembered too fondly due to its propensity to fail.

But unlike that system, the new JL’s axle disconnect is not vacuum-controlled, but rather electric, so it should be more reliable. And even if it’s not, I’m sure the aftermarket will come up with a bypass option or even a one-piece axle shaft kit
.”

I still doubt the benefits of the axle disconnect on a vehicle that isn’t a hyer-economy vehicle, but if it isn’t intrusive then OK, but again another item to keep an eye on with early feedback. It makes much more sense in a Trans-axle as well vs a RWD configuration.
 

Matt The Hammer

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The same system was on the JKs. The front sway bar disconnect. Ironically the part that fails with them is the electric motor. Well, not the actual motor, the circuit board that controls it.

So, good luck with that. My YJ has the posi-lock cable installed. Never had issue after put that on.
 

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The same system was on the JKs. The front sway bar disconnect. Ironically the part that fails with them is the electric motor. Well, not the actual motor, the circuit board that controls it.

So, good luck with that. My YJ has the posi-lock cable installed. Never had issue after put that on.
No, this is different than front sway bar disconnect. Front Axle Disconnect actually disconnects one side of the front axle shaft so it kind of works like locking hubs. One of the axle shafts (right side) is actually two pieces so it allows the right tire to spin free similar to an unlocked hub. The left tire also spins (locked hub), in turn spinning the left axle shaft and internal diff gears and the other half of right axle shaft. The ring and pinion stay stationary along with the front drive shaft.

I'm really surprised there was never any mention of this from previous leaks.

Not liking that it's present. Just seems like one more system to fail.

Also wonder if it's standard on all trim levels or just the Rubicon.

Do we have any good pictures of the front axles? You would be able to see the mechanism housing on the axle tube.

maxresdefault.jpg


95n586.jpg
 
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Matt The Hammer

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Yeah, it's the same as the sway bar disconnect.

2SplitOpen.jpg


I've torn apart and rebuilt both this and the YJ system. The sway bar disconnect only really allows the bar to spin freely on both sides. Thus, 'disconnected'. But the bar isn't detached from the body like some of the aftermarket sway bar disconnects.

163_0410_06z-2005_dodge_power_wagon-smart_bar_view.jpg


You can see that the bar, even disconnected from the other side, is still attached to the frame of the Jeep.

Unlike the other style where the link to the axle is detached and stored up on the frame:

19105-installing-sway-bar-disconnects-your-jeep-wrangler-swaybar-stored-jeep-sway-bar-disconnect.jpg
 
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Jeepsterfreak

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Yeah, it's the same as the sway bar disconnect.
Sorry, I'm not following you. Are you pointing out the new JL Front Axle Disconnect mechanism is similar to the sway bar disconnect mechansim because it's now electronic and not vacuum controlled?

I thought the TJ and JK did away with a Front Axle Disconnect system but now it's back on JL?
 

stewartld

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Can someone explain why the Select Trac is only on Sahara but not Rubicon? Maybe the Rubicon will come with this standard?
Selectrac IS standard on the Rubicon in Europe....
 

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So, I have looked (online) at about 5 different dealers in Texas and Colorado. I looked for a 2019 Sahara with Selec-trac....... I didn’t find any.

Do folks here have any thoughts as to why? Not a popular option?

I am trying to figure out the pros and cons of this option. I am a newbie and all I can see are pros — seems like full time 4wd is a big plus and I would have expected that many Sahara’s on the lot would have it. Why not? Thoughts?
 

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So, I have looked (online) at about 5 different dealers in Texas and Colorado. I looked for a 2019 Sahara with Selec-trac....... I didn’t find any.

Do folks here have any thoughts as to why? Not a popular option?

I am trying to figure out the pros and cons of this option. I am a newbie and all I can see are pros — seems like full time 4wd is a big plus and I would have expected that many Sahara’s on the lot would have it. Why not? Thoughts?
If you are normal driver I agree its nothing but pros. However if you are a hardcore rock crawler, the tcase and drive train linkages are not as strong, also the mp3022 tcase (selec trac you are asking about) does not offer the 4:1 low range you will get with the Rock Trac tcase.

Another thought is traditionally Jeep has not offered this type of tcase in a wrangler so they are starting out small and seeing the take rate. Now that Jeep offers more and more creature comforts it is really opening up the market for JLs to folks who otherwise may not have been interested in a rough riding SFA 4x4, I think as this customer base grows you will see more selec tracs in wranglers.

If I had my way I would get the NP242 tcase from the 90s. That was the original selec trac tcase and it offered true full time 4wd, where the newer mp3022 relies on censors to send power as needed, this causes there to be an ever so slight delay before the front wheel engages.
 

Dkretden

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If you are normal driver I agree its nothing but pros. However if you are a hardcore rock crawler, the tcase and drive train linkages are not as strong, also the mp3022 tcase (selec trac you are asking about) does not offer the 4:1 low range you will get with the Rock Trac tcase.

Another thought is traditionally Jeep has not offered this type of tcase in a wrangler so they are starting out small and seeing the take rate. Now that Jeep offers more and more creature comforts it is really opening up the market for JLs to folks who otherwise may not have been interested in a rough riding SFA 4x4, I think as this customer base grows you will see more selec tracs in wranglers.

If I had my way I would get the NP242 tcase from the 90s. That was the original selec trac tcase and it offered true full time 4wd, where the newer mp3022 relies on censors to send power as needed, this causes there to be an ever so slight delay before the front wheel engages.
Thank you.

I have now found a dealership with several selec-trac units in inventory. So, they are “out there if you look”.

Much more research needed on my part before deciding. I am unlikely to ever be a dedicated off-road enthusiast. Mostly a city boy who likes to get away every now and then.

Thanks for the input!
 

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