Damage to transfer case by using 2wd?

[NewMexicoBoondocker]

The front driveline does NOT turn in that mode, force 2wd will even work in 4 low. So I’m assuming the Tcase uses clutches to activate 4wd.

The only thing I can think of is if he didn’t realize I was using a taser to go to 2wd drive. If the Jeep was trying to use all wheel drive and the front hubs weren’t locked, then I could see issues.

As a point of clarity to your discussion, last I knew the JL doesn't have selectable locking/unlocking front hubs. Correct? If that's the case, the front driveline (axle shafts, ring/pinion, driveshaft) is always turning even if you have the t-case in 2wd. In 2wd, the t-case is simply not sending power to the front driveline but the driveline is, nonetheless, still spinning.

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[DavidArmen]

wait. 392s are AWD?

4WD auto, not AWD.

 

[DavidArmen]

As a point of clarity to your discussion, last I knew the JL doesn't have selectable locking/unlocking front hubs. Correct? If that's the case, the front driveline (axle shafts, ring/pinion, driveshaft) is always turning even if you have the t-case in 2wd. In 2wd, the t-case is simply not sending power to the front driveline but the driveline is, nonetheless, still spinning.

the JL has a FAD. The 392 does not. So yes, that’s correct but only for the 392. The regular JLs disconnect the front axle using the FAD in 2 wheel drive mode.

 

[DavidArmen]

It doesn’t look like they have them on their site yet. Here’s his FB posthttps://www.facebook.com/OfficialCaseyCurrie/posts/524552422367486

Yes, using the Tazer for force2wd. The front driveline does NOT turn in that mode, force 2wd will even work in 4 low. So I’m assuming the Tcase uses clutches to activate 4wd.

That unfortunate if it uses clutches even for 4Hi part time and even for 4low. The regular rubicon transfer case completely locks both axles using a very heavy duty chain in the t-case. Clutches, no matter how locked, will never be as strong as a chain (or gears with the Atlas).

 

[NewMexicoBoondocker]

the JL has a FAD. The 392 does not.

Good to know. I didn't realize they used a FAD on the JL but just read up on it after your post. My last Wrangler was a JK.

 

[1996cc]

As a point of clarity to your discussion, last I knew the JL doesn't have selectable locking/unlocking front hubs. Correct? If that's the case, the front driveline (axle shafts, ring/pinion, driveshaft) is always turning even if you have the t-case in 2wd. In 2wd, the t-case is simply not sending power to the front driveline but the driveline is, nonetheless, still spinning.

yes, but if you have selectable hubs as we are discussing here with the Currie axles, that doesn’t apply. This discussion is not about factory axles.

 

[NewMexicoBoondocker]

yes, but if you have selectable hubs as we are discussing here with the Currie axles, that doesn’t apply. This discussion is not about factory axles.

Got it, my fault. I didn't read carefully!

 

[MSparks909]

That unfortunate if it uses clutches even for 4Hi part time and even for 4low. The regular rubicon transfer case completely locks both axles using a very heavy duty chain in the t-case. Clutches, no matter how locked, will never be as strong as a chain (or gears with the Atlas).

I think I read somewhere that this transfercase uses clutches for 4 Auto and a chain for 4 Hi/4 Low.

 

[stumblinhorse]

I think I read somewhere that this transfercase uses clutches for 4 Auto and a chain for 4 Hi/4 Low.

All I read is that the clutches are locked in 4lo.

 

[MSparks909]

All I read is that the clutches are locked in 4lo.

After more research I stand corrected. If it becomes a problem I’ll either toss in a standard chain driven Rubicon tcase or an Atlas.

 

[Bzinsky]

the same transfer case is used on the 4xe, the 4xe makes the same torque as the 392. You can select 2wd in the 4xe.

But……The 4xe cuts power in 2wd mode at low speed. There is a full second difference in 0-60 between 2wd and awd mode in the 4xe. It appears like it cuts power in 1st gear, which is obviously to reduce torque on some aspect of the drivetrain after the transmission. Not sure if it’s transfer case, rear diff, driveshaft, or axles, but I would assume they did do it for a reason. I believe most of the 4xe drivetrain is the same as the 392 though.

I currently drive a 2014 gmc sierra with a tuned L86. Probably about the same low end powerband as the 392. This has a similar transfer case, but it has 2hi, 4auto, 4hi, and 4low. This has no torque restrictions in 2wd.

4auto is effectively the same as awd. The fact that most awd system torque vector through applying some shitty individual wheel braking system does not mean this is not awd. The difference between traditional 4wd and awd is the center diff. Awd has a center diff and 4wd only has lock and unlock. The clutch based transfer case for 4auto, is effectively a clutch based center diff.

That being said, 4auto is the greatest shit ever. I’ve done hundred of 4auto launches with my truck. It gets traction just like a locked 4wd transfer case, responds almost instantaneously to wheel slip to the point where you almost don’t get any, and in my experience is incredibly stout.

Now I will say, when 4auto is enabled in my truck, and it’s not detecting slippage, it’s still sending 5% power to the front at all times.

I’m not exactly sure what is deactivated when you enter 2wd mode in my truck and the 4xe. But they do effect mpg. Maybe it is the front axle that’s disconnected front the front driveshaft, not sure.

My point being, your 392’s might not have this piece of hardware in them to run in true 2wd mode and using a tazer to force it into 2wd might just be the same as keeping 4auto activated but it’s not sensing and wheel slippage so it doesn’t send power to the front. There would be no advantage to this other than your vehicle just won’t send power to the front when called for (well and burnouts)

Also, important thing to point out is, 4auto has a scenario when it is not good to use. When you’re driving in constant snow or mud. Your clutches are just going to activating and deactivating constantly and I guess will just cause additional wear. This is when gm recommends switching to 4hi or 4lo to lock the transfer case.

So if you guys only have 4auto and 4 low selectors, i’d be switching into 4 low for like a muddy situation. Obviously doesn’t make sense to drive around in low range on public roads because there is some snow out.

There is a guy on the 4xe forums who did some testing on when the transfer case is sending power to the front in 4auto, 4hi, 4lo and it was pretty interesting. You guys can do this with an obd2 reader. Unfortunately, I don’t believe the transfer case was truely locked in the 4xe. Guessing its the same with the 392.

 

[MSparks909]

I’ve been using ForceRWD and unlocked hubs on my 392 since I did the XD60/60 swap. Big difference in steering feel compared to 4Auto/locked hubs and I really enjoy not having the front driveline spin when it’s not needed. Time will tell if this causes any issues long term but if I do end up having issues I’ll probably just swap to a standard Rubicon t-case and call it good.

For those wanting to keep 4Auto functionality like the factory setup after an axle swap, especially on dry pavement, spring for the RCVs up front. I get a good bit of u-joint bind on the pavement in 4Auto/locked hubs, which is to be expected.

 

[Wicked3.0]

I have had Force RWD on since I upgraded my front drive shaft to a Tom Wood's 1350 about 6 months ago, due to getting a 3.5 Game Changer lift. The reason why I leave it in Force RWD is because I have noticed that between 50mph - 58mph I get a vibration noise from the front driveshaft. Almost sounds like exhaust drone, but it's not. If I go slower or faster than that speed in 4HighAuto, it goes away. OR if I leave it in Force RWD, during 50mph - 58mph, that vibration is not there!

However, the only problem I have had so far leaving in Force RWD over the last six months:


About 1 or 2 times per month, when I randomly start the Jeep (pulling out of my driveway, after I get gas, when I leave work) and I TURN getting out of the parking spot, it's like the Jeep is in 4Low (same binding / locked up turning that you experience if you are in 4Low and you are on pavement (not a great feeling!). I immediately go to the Tazer menu and select "OFF" for Force RWD and all goes back to normal and the Jeep seems to instantly "relax".

I Would love to see any input or thoughts from anyone here about this. My guess is a software glitch on certain start ups?

Cheers

 

[1996cc]

I have had Force RWD on since I upgraded my front drive shaft to a Tom Wood's 1350 about 6 months ago, due to getting a 3.5 Game Changer lift. The reason why I leave it in Force RWD is because I have noticed that between 50mph - 58mph I get a vibration noise from the front driveshaft. Almost sounds like exhaust drone, but it's not. If I go slower or faster than that speed in 4HighAuto, it goes away. OR if I leave it in Force RWD, during 50mph - 58mph, that vibration is not there!

However, the only problem I have had so far leaving in Force RWD over the last six months:


About 1 or 2 times per month, when I randomly start the Jeep (pulling out of my driveway, after I get gas, when I leave work) and I TURN getting out of the parking spot, it's like the Jeep is in 4Low (same binding / locked up turning that you experience if you are in 4Low and you are on pavement (not a great feeling!). I immediately go to the Tazer menu and select "OFF" for Force RWD and all goes back to normal and the Jeep seems to instantly "relax".

I Would love to see any input or thoughts from anyone here about this. My guess is a software glitch on certain start ups?

Cheers

Are you starting it up and pulling out immediately? I’ve noticed, it takes the jeep computer a few seconds to boot up, and then the Tazer another few seconds to calibrate itself as well. Try letting all the dash warnings cycle through, etc before you drive off.

Very rarely the Tazer has forgot that I was in force RWD and I just have to turn it back on. Make sure to set a quick button to to that. Then it’s super fast, just push a cruise button and it’s back on…

 

[Wicked3.0]

Are you starting it up and pulling out immediately? I’ve noticed, it takes the jeep computer a few seconds to boot up, and then the Tazer another few seconds to calibrate itself as well. Try letting all the dash warnings cycle through, etc before you drive off.

Very rarely the Tazer has forgot that I was in force RWD and I just have to turn it back on. Make sure to set a quick button to to that. Then it’s super fast, just push a cruise button and it’s back on…

I understand completely what you are saying about the Tazer taking a few seconds to calibrate.

Today when it happened to me, it was actually started up for about 3 minutes before putting it in Reverse and the Jeep started locking up when turning.

It's always in Force RWD and I've never had it "forget" it's just that it locks up every so often (about once a month) just at start up. To remedy the "lock up" I turn off Force RWD, it settles / relaxes, and then I place Force RWD back on and it's back to normal.

I reached out the Z Automotive to see what they think about it.

Thank you for the guidance and I agree I will need to set a quick button to make it easier as well.

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