Thats all good. If you want to talk other manufacturers sure. I think you are mistaking Auto-4WD for full time 4WD.

 

What you are describing is Permanent 4WD, where there is no 2WD option.. Mike is correct, "Full-time" refers to systems that are capable of running in 4WD all the time. The Tahoe/Yukon, for example, have full-time 4WD, and have a **** similar to the one pictured above, with 2Hi/Auto/4Hi/4Lo options selectable.

 

That is not true. Permanent is full time or full time is permanent. The full time naming implies 4WD is in 4WD "full time". Full time also denotes the presence of 4LO and a locking centre differentIal. The Tahoe and Yukon cannot run 4H permanently on dry pavement . Auto 4WD goes from 2-4 but never forever, it requires and needs slipping to engage 4H.

Escalade is full time. Tahoe or Yukon are not full time. Edit. Esacalade is not full time. 4H in the GM set ups are the equivalent of centre differential lock on the 4Runner Limited. When centre diff is locked, you cannot drive the 4Runner limited on dry ground. Once you lock the centre diff on the limited 4Runner, you are now the equivalent of the 4H on a Tundra or the 4H on the Tahoe. The Tahoe or Yukon lack a centre differential.

Here is the GM set up :

• Driver-selectable two-speed transfer case on 4WD models
• Includes a 4-position **** (2WD high, AUTO, 4 HI, 4 LOW and neutral)
• When in AUTO mode, remains in 2WD mode until the system detects wheel slippage
• Automatically engages 4WD until traction is regained
• Allows driver shift-on-the-fly capability from 2WD to 4WD at any speed, using the rotary control
• Provides a neutral position for dinghy/flat towing behind another vehicle

I am really amazed how many people are unfamiliar with Toyota full time set ups.


Here is the Toyota Set Up:

1. Part time 4WD requires the driver to select between 2WD mode and 4WD mode. When in 2WD mode, the vehicle is being driven by the rear wheels.
2. Full time 4WD allows both the front and rear wheels to drive the vehicle all the time.
3. Full time 4WD with multi-mode selection allows the driver to switch between 2WD and part time/full time 4WD modes. When in 2WD mode, the vehicle is being driven by the rear wheels.
4. Full time AWD allows variable power to be delivered to both front and rear wheels based on road conditions.
5. Full time 4WD on-demand defaults the drive power to the front wheels, sending power to rear wheels as needed based on road conditions.

Note: Toyota is sort of cheating on #3

 

That would be a big no. Since the dawn of time (or at least the 80s, which sometimes feels like the same thing), "full-time 4wd" has meant that a vehicle has a 4-wheel drive system that can be used all the time if the driver wishes. My first experience with this was on Jeeps, where the "Selec-trac" system was part time and had to stay in RWD on dry ground or risk damaging the driveline; While the "Quadra-trac" system was full-time, so you could use 2Hi or 4Hi at will, regardless of terrain.

Incorrect again. I have personally driven these vehicles, on dry ground, in 4Hi, for thousands of miles. Probably tens of thousands in Auto. On that note, do you really think a manufacturer would include an "Auto" mode for its 4wd system, if accidentally activating at the wrong time meant potentially destroying the driveline?

You are correct about one thing here, the Tahoe/Yukon/Escalade does in fact not have a center differential. Instead, clutches in the transfer case perform roughly the same duty.

 

This thread reminds me all automakers have done a TERRIBLE job of explaining AWD/4WD systems.

toyota has a wide range of implementations from weaksauce to stout.

Jeep has a pretty concise set of 4wd systems with varying abilities. Good read here: https://www.jeep.com/4x4.html

 

What Jeep did you have that had 2LO as well as Quadra-Trac?

The GM manuals clearly state that the their 4WD 4HI settings are to not be used on dry pavement. There is no centre diff in those models, it has a transfer case in place.

 

I've never seen a Jeep--or for that matter, a vehicle of any brand--with a dedicated 2Lo setting, though as you'll see below, some could theoretically get there when two separate controls are involved.

I did have my names mixed up though. Command-trac is the part-time system, select-trac the full-time, and quadra-trac is the permanent. Here's some info on Selec-trac:



I became familiar with these systems due to several friends having Cherokees and Grand Cherokees, and very nearly buying a GC myself.

 

Meant 2HI. Not 2LO. When I have a chance I will look at select trac. Thanks for posting that.

 

Correct....I haven't, either. Wouldn't be any sense in it. Low-range is for maximum torque-multiplication and off-road traction, where you are almost always going to be 4WD to start with.

I've noticed one pattern with Jeep over the years. Perhaps because of its rock-crawling nature, even now, in 2019, from what I can tell (and I may be wrong on this), Jeep has never made the Select-Trac or Quadra-Trac systems available on the Wrangler. Like it or not, one is stuck with the part-time Command-Trac. The Wrangler, of course, is popular enough as it is, but, even so, they may still be losing some sales by offering only part-time 4WD systems.

 

The Wrangler is available with Selec-Trac as a $595 option in the Sahara trim, and only with the automatic transmission. Models below (Sport and Sport S) have Command-Trac as the only option, and ones above (Rubicon and Moab) have Rock-Trac as the only option.

I had thought that would also mean that the Gladiator would offer Selec-Trac in the equivalent Overland trim, but that does not appear to be the case.

 

Thanks for the discussion. You have certainly broadened my horizons regarding the Jeep 4X4 systems.

Here is my take, lets see if we agree:

Jeep calls their Quadra-Drive a full-time 4 wheel drive system: full-time 4x4 system so it’s always active. https://www.jeep.com/4x4.html There is no 2WD
Jeep calls their Quadra-Trac a full time 4 wheel drive system: 4x4 System is an active full-time 4x4 system that functions in 4x4 mode until additional traction is needed.
Jeep calls their Select-Trac a 4WD with a full time mode: a full time mode that will automatically switch from 2WD to 4WD
Toyota calls their 4Runner Limited full-time 4WD system....https://www.toyota.com/4runner/featu...8664/8666/8668

I know you separate full-time 4WD system and permanent 4WD system, but I do not agree. They are the same. Jeep does not refer to their full-time system as permanent, neither does Toyota. The select trac is not a full-time 4WD system, its a selectable 2WD/4WD system with a full-time mode.

What are your thoughts? Looking forward to your response.

 

Trying to close the gap a bit, how about this? A full-time 4WD system is any that is designed to be driven on dry roads and can make tight turns on said surfaces without damage. A permanent 4WD system is a specific subset of full-time systems, where 4WD cannot be disabled without making mechanical modifications to the vehicle.

 

Interesting way to put. I just think the name full-time, means by default it is in 4WD...if there was a 2WD option for a full-time system, then it is not full time. Or a full time mode.

....Mercedes uses permanent for their awd system in their G-wagon, something I did not know (until we started to discuss). They omit the words four-wheel-drive for the G-wagon...Toyota and Jeep both use full-time.

Thanks for the discussion.