Confused about the 392 transfer case

[HearHear]

Hello, how do you use the 392 transfer case? My 392 is on the way, but I need to know how to use it.
I understand what the different gears are for, but I’m mainly confused about 4High Auto. I read that with the 392 you’re supposed to be in 4High Auto for daily normal driving. But I read elsewhere this could damage the drive train. What is correct?

 

[Viking Jeeper]

You should download and read the online version of the owners manual, there is a 392 performance supplement that explains all of this. The 4H Auto is the normal position for daily driving. 4H part time is for off-roading in high gear.

 

[HearHear]

You should download and read the online version of the owners manual, there is a 392 performance supplement that explains all of this. The 4H Auto is the normal position for daily driving. 4H part time is for off-roading in high gear.

I read the supplement and it’s confusing. In part it says, quote:

“This transfer case is designed to be driven in the four-wheel drive position (4H AUTO) for normal street and highway conditions on dry hard surfaced roads.
For variable driving conditions, the 4H AUTO mode can be used. In this mode, the front axle is engaged, but the vehicle's power is sent to the rear wheels. Four-wheel drive will be automatically engaged when the vehicle senses a loss of traction.
In the event that additional traction is required, the transfer case 4H AUTO and 4L positions can be used to lock the front and rear driveshafts together, forcing the front and rear wheels to rotate at the same speed. The 4H AUTO and 4L positions are intended for loose, slippery road surfaces only and not intended for normal driving. Driving in the 4H AUTO and 4L positions on hard-surfaced roads will cause increased tire wear and damage to the driveline components.”

The last two sentences basically state 4High Auto must not be used for daily driving. But that contradicts what I previously learned about 4High Auto and that it’s supposed to be used for daily driving on hard surfaces.

 

[Proptrash]

Hello, how do you use the 392 transfer case? My 392 is on the way, but I need to know how to use it.
I understand what the different gears are for, but I’m mainly confused about 4High Auto. I read that with the 392 you’re supposed to be in 4High Auto for daily normal driving. But I read elsewhere this could damage the drive train. What is correct?

Part time 4WD is only for “part of the time” like snow, Ice, rock climbing etc. ie “part time”. Confusing I know, but in part time the front and rear will be working all at once (true 4WD). Don’t want to be in part time on dry roads 100% of the time.

 

[Turboencabulator]

"In the event that additional traction is required, the transfer case 4H AUTO and 4L positions can be used to lock the front and rear driveshafts together, forcing the front and rear wheels to rotate at the same speed. The 4H AUTO and 4L positions are intended for loose, slippery road surfaces only and not intended for normal driving. Driving in the 4H AUTO and 4L positions on hard-surfaced roads will cause increased tire wear and damage to the driveline components.”

I think it's a typo. They are describing 4H Part Time and 4L (low). The 392 is designed to be driven in 4H AUTO on hard surface roads where basically the MP3022 transfer case uses an electronically controlled clutch to send 100% power to the back wheels but if it senses wheel slip (like a smokey burnout ) it can go up to a 50%/50% split between the front wheels/back wheels. Now in 4H PART TIME and 4L the transfer case is forced into a split 50%/50% front wheel/back wheel and that is the position that they say "on hard-surfaced roads will cause increased tire wear and damage to the driveline components." Interestingly in the 392 supposedly you can lock the rear differential in 4H Part Time not just 4L (low) like other Jeep Rubicons which is kinda cool.

But I don't have my 392 yet (2022 order) so others may be better informed.

 

[Viking Jeeper]

There IS a typo, I had not read the more detailed part before. This is correct:

This is wrong:

 

[Zirk]

I think it's a typo. They are describing 4H Part Time and 4L (low). The 392 is designed to be driven in 4H AUTO on hard surface roads where basically the MP3022 transfer case uses an electronically controlled clutch to send 100% power to the back wheels but if it senses wheel slip (like a smokey burnout ) it can go up to a 50%/50% split between the front wheels/back wheels. Now in 4H PART TIME and 4L the transfer case is forced into a split 50%/50% front wheel/back wheel and that is the position that they say "on hard-surfaced roads will cause increased tire wear and damage to the driveline components." Interestingly in the 392 supposedly you can lock the rear differential in 4H Part Time not just 4L (low) like other Jeep Rubicons which is kinda cool.

But I don't have my 392 yet (2022 order) so others may be better informed.

I have mine and I believe you can only lock in in 4L.

 

[Turboencabulator]

I don't have mine yet so I am sure your right about manually locking only working in 4L and not 4H. I have read in several reviews below that Locking the Rear Diff in 4H may be something the 392 does automatically in Off Road Plus mode for "High Speed Running". Here are some articles describing it:

From UTX Driver:

From Hagerty:

From Car and Driver:

 

[Viking Jeeper]

I seriously doubt the rear will be locked automatically in off road plus. That is a separate command.

 

[kbernard]

i live at the beach and wheeled up a ramp to look at the ocean and it went right up the sand ramp like it was in 4wd. When I backed down the ramp you could tell it was fine and when the rear tires spun a little the front kicked in. So if I was going to go on the beach I would shift it to 4half time so it would be engaged the whole time not just for when the rear looses traction. There is the only 3 selections so there is no 2wd like the regular 6cyl jeeps.

 

[CBH]

I think it's a typo. They are describing 4H Part Time and 4L (low). The 392 is designed to be driven in 4H AUTO on hard surface roads where basically the MP3022 transfer case uses an electronically controlled clutch to send 100% power to the back wheels but if it senses wheel slip (like a smokey burnout ) it can go up to a 50%/50% split between the front wheels/back wheels. Now in 4H PART TIME and 4L the transfer case is forced into a split 50%/50% front wheel/back wheel and that is the position that they say "on hard-surfaced roads will cause increased tire wear and damage to the driveline components." Interestingly in the 392 supposedly you can lock the rear differential in 4H Part Time not just 4L (low) like other Jeep Rubicons which is kinda cool.

But I don't have my 392 yet (2022 order) so others may be better informed.

When I owned a previous Jeep that was normally driven in 2H, I was told I needed to occasionally put it into Part Time 4H and 4L to “exercise" those components that are not engaged in 2H. With the Rubicon 392 normally running in 4H Auto, do I still need to occasionally run it in Part Time 4H and 4L to properly maintain the 4-Wheel Drive Systems.

 

[Viking Jeeper]

When I owned a previous Jeep that was normally driven in 2H, I was told I needed to occasionally put it into Part Time 4H and 4L to “exercise" those components that are not engaged in 2H. With the Rubicon 392 normally running in 4H Auto, do I still need to occasionally run it in Part Time 4H and 4L to properly maintain the 4-Wheel Drive Systems.

Yes, its good practice. Gears, shifters, actuators, need to be exercised.

 

[CBH]

Yes, its good practice. Gears, shifters, actuators, need to be exercised.

I sent the same question to Customer Care at MOPAR.com. I just received an e-mail response from them that basically posted a copy of the “4-Wheel Operation” section of the Owner’s Manual -- no help. Yesterday I received a phone call from Jeep Wave. The representative did not know what the issue was and knew nothing about Jeep 4-Wheel Drive Systems; so I repeated my question to him. He reminded me of a door greeter at Lowes whom I asked, “Where do keep the WD-40?”; and she responded, “What’s WD-40?”

 

[Viking Jeeper]

I sent the same question to Customer Care at MOPAR.com. I just received an e-mail response from them that basically posted a copy of the “4-Wheel Operation” section of the Owner’s Manual -- no help. Yesterday I received a phone call from Jeep Wave. The representative did not know what the issue was and knew nothing about Jeep 4-Wheel Drive Systems; so I repeated my question to him. He reminded me of a door greeter at Lowes whom I asked, “Where do keep the WD-40?”; and she responded, “What’s WD-40?”

Perfect.......

 

[CBH]

Perfect.......

Got another e-mail from FCA Customer Care. Here’s what Gerald wrote:

"Unfortunately, we have to refer you to your servicing dealership for further help. I am not a mechanic, but I am sure using the other modes occasionally would not hurt. This will help to keep the internals lubed and oiled. It is better to use occasionally than not."

Unfortunately, I didn’t ask if using the Part Time system would hurt...I asked if NOT USING the Part Time System could hurt. Here’s why....I suspect some Rubicon 392 owners will never engage the Part Time 4H or 4L Systems as they enjoy the default 4H Auto system for day to day driving. All I want to know was...are these people damaging the Part Time Systems by never engaging them?

I didn’t ask them to solve World Hunger, I just asked them a simple question about the systems they built and sold to me, the same systems that have been in Jeeps for decades. Maybe FCA Customer Care representatives go through the same training program as the Lowes greeter who had never heard of WD-40.

 

[CBH]

Got another e-mail from FCA Customer Care. Here’s what Gerald wrote:

"Unfortunately, we have to refer you to your servicing dealership for further help. I am not a mechanic, but I am sure using the other modes occasionally would not hurt. This will help to keep the internals lubed and oiled. It is better to use occasionally than not."

Unfortunately, I didn’t ask if using the Part Time system would hurt...I asked if NOT USING the Part Time System could hurt. Here’s why....I suspect some Rubicon 392 owners will never engage the Part Time 4H or 4L Systems as they enjoy the default 4H Auto system for day to day driving. All I want to know was...are these people damaging the Part Time Systems by never engaging them?

I didn’t ask them to solve World Hunger, I just asked them a simple question about the systems they built and sold to me, the same systems that have been in Jeeps for decades. Maybe FCA Customer Care representatives go through the same training program as the Lowes greeter who had never heard of WD-40.

Just received a response from a Jeep Wave “Corporate Resource” that reads:

"Driving in 4 wheel auto in 4 x 4 applications will not harm the other gears as the transfer case is a lubricated system and all components are lubricated at all times. If he is using this during regular street driving on dry pavement that could damage his system."

 

[Viking Jeeper]

Just received a response from a Jeep Wave “Corporate Resource” that reads:

"Driving in 4 wheel auto in 4 x 4 applications will not harm the other gears as the transfer case is a lubricated system and all components are lubricated at all times. If he is using this during regular street driving on dry pavement that could damage his system."

God help us......