Toyota full time 4-Wheel Drive
07-04-19, 02:37 PM
#16
Lexus Fanatic
Thread Starter
07-04-19, 02:46 PM
#17
Super Moderator
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.
07-04-19, 02:51 PM
#18
Lexus Fanatic
Thread Starter
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.
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
Last edited by Toys4RJill; 07-04-19 at 03:25 PM.
07-04-19, 08:32 PM
#19
Super Moderator
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.
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.
07-04-19, 09:27 PM
#20
Lexus Fanatic
iTrader: (20)
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
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
07-05-19, 04:56 AM
#21
Lexus Fanatic
Thread Starter
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.
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.
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.
07-05-19, 05:09 AM
#22
Super Moderator
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.
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:
Selec-Trac was first introduced in the full-size Jeeps (SJ) in 1983 using the New Process NP228 and NP229 transfer cases. These are very similar to the Quadra-Trac NP219 transfer case described in the next section below. The differences are 1) they added a 2WD mode for fuel savings and 2) the 2WD-to-4WD modes were controlled via a vacuum switch on the dashboard. The Hi-N-Lo range selection was still performed using a shift lever on the console. The NP228 differs from the NP229 by not having the viscous coupling in 4WD Hi mode, reverting to a simpler open center differential. Both transfer cases still lock the center differential in 4WD Lo mode. The NP228/229 transfer cases were available in the full-size Jeeps from 1983 to 1991. The NP228 was also available in the XJ Cherokee and Wagoneers and the MJ Comanche pickups from 1984 until replaced by the NP242 in 1987. Several companies have offered a dual shift lever conversion which replaces the vacuum switch and solenoid with a more reliable second console lever for 2WD-4WD mode selection.
The NP242 Selec-Trac transfer case debuted alongside the Fuel-Injected 4.0L Inline-6 in the compact Jeep Cherokee in 1987. The shifter has modes 2WD - 4WD Hi Part-Time - 4WD Hi Full-Time - N - 4WD Low. There is a center differential that is open in 4WD Hi Full-Time mode and distributes torque 48/52% front-to-rear. This mode can be used on dry pavement or slippery surfaces with only a small fuel mileage penalty compared to 2WD mode. In 4WD Hi Part-Time and 4WD Low, the center differential is mechanically locked, so these modes are for slippery surfaces only.[3] Low range engages a 2.72:1 planetary gear ratio for increased torque and low speeds. Overall, this system functions very much like the NP228 transfer case above, just with all of the mode and range controls via a single, console-mounted shift lever. It was available in the 1987 to 2001 XJ Cherokee and Wagoneer, the 1987 to 1992 MJ Comanche, the 1993 to 2004 ZJ and WJ Grand Cherokees, the 2002 to 2007 KJ Liberty, and the 1998 to 2000 Dodge Durango. It was replaced in the 2005 Grand Cherokee by the Quadra-Trac II system featuring the NV245 transfer case with 4WD Auto mode and in the 2008 KK Liberty by Selec-Trac II using the MP3022 transfer case.
The NP242 Selec-Trac transfer case debuted alongside the Fuel-Injected 4.0L Inline-6 in the compact Jeep Cherokee in 1987. The shifter has modes 2WD - 4WD Hi Part-Time - 4WD Hi Full-Time - N - 4WD Low. There is a center differential that is open in 4WD Hi Full-Time mode and distributes torque 48/52% front-to-rear. This mode can be used on dry pavement or slippery surfaces with only a small fuel mileage penalty compared to 2WD mode. In 4WD Hi Part-Time and 4WD Low, the center differential is mechanically locked, so these modes are for slippery surfaces only.[3] Low range engages a 2.72:1 planetary gear ratio for increased torque and low speeds. Overall, this system functions very much like the NP228 transfer case above, just with all of the mode and range controls via a single, console-mounted shift lever. It was available in the 1987 to 2001 XJ Cherokee and Wagoneer, the 1987 to 1992 MJ Comanche, the 1993 to 2004 ZJ and WJ Grand Cherokees, the 2002 to 2007 KJ Liberty, and the 1998 to 2000 Dodge Durango. It was replaced in the 2005 Grand Cherokee by the Quadra-Trac II system featuring the NV245 transfer case with 4WD Auto mode and in the 2008 KK Liberty by Selec-Trac II using the MP3022 transfer case.
I became familiar with these systems due to several friends having Cherokees and Grand Cherokees, and very nearly buying a GC myself.
07-05-19, 06:12 AM
#23
Lexus Fanatic
Thread Starter
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.
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.
07-05-19, 06:54 AM
#24
Lexus Fanatic
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.
07-05-19, 07:11 AM
#25
Super Moderator
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.
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.
07-05-19, 12:01 PM
#26
Lexus Fanatic
Thread Starter
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.
Last edited by Toys4RJill; 07-05-19 at 01:22 PM.
07-07-19, 04:59 AM
#27
Super Moderator
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.
What are your thoughts? Looking forward to your response.
07-07-19, 05:17 AM
#28
Lexus Fanatic
Thread Starter
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.
....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.
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