Please excuse this newbie's ignorance, but I have a burning question(s). We traded in our Honda CRV with the "Realtime" 4wd for a 4x4 Armada SE. My question is rather rambling, so I'll try to be precise. I understand front-wheel based AWD systems such as the Subaru and Audi: Basically front wheel drive vehicles with the addition of varying percentages of back wheel drive power depending on road conditions. I know that our CRV AWD was a front wheel drive vehicle most of the time unless front wheel slippage was detected, then the rear wheels would pitch in. I think that the MDX and Pilot are similar, though more advanced versions of this idea. I think the Highlander AWD is a fulltime system split 50/50 or so, like some of the Subarus.
My main question is the system found on my Armada versus that found on Tahoes/Suburbans, Expeditions and the new 4 Runners and Sequoias. I understand that the "Auto" selection on my Armada means RWD unless slippage occurs, then part time 4wd untill traction is regained. Is this correct? I gather from the owner's manual that the 4H should only be used in slippery conditions of ice, rain, snow or offroad. It should not be used on dry pavement to duplicate an "AWD" drive vehicle. Is this correct?
Is the Armada similar in this regard to Ford/Chevy/Toyota trucks? I thought that the Toyota Sequoia may be driven in 4WD Hi on pavement. I understand that my friend's V8 2003 4runner is a "fulltime all wheel drive" system which can be driven in any condtions, with the ability to lock the center differential. My other friend has an Escalade with a non-adjustable awd system.
What are the advantages/disadvantages between the Armada (and I think other Nissans use the same system) and an a fulltime 4wd system usuable on dry pavement and the above mentioned awd systems? Can you folks clarify for me how all these systems work and their pros and cons?
Is their an advantage to a locking center or front/rear axle differential? Does the Armada have a center locking differential?
Sorry for the rambling and all of the questions, and of course, for the mis-use of terminology.
We use our vehicles in the snow during ski season, but principally have a nice dry climate where RWD or FWD does just fine.
Typically, a part-time 4x4 system will have four modes: 2Hi, 4Hi, N, and 4Lo. Typically, each of the 4x4 modes lock the transfer case, which means you'll have problems on dry pavement, thus, only for use on snow or dirt, etc. But even in 2Hi, the front hubs are still "locked" meaning you are not seeing any fuel economy savings, because the entire front drivetrain is still turning.
Typically, full-time 4x4 systems have three choices, AWD, N, and 4Lo. If you have the shifter in AWD, all four wheels do the driving, with a center differential to allow for tire slippage. We had a Grand Cherokee with this type system. I do think it was mostly RWD, with the option to vary the torque to the front as necessary. If you put it in 4Lo, like the part-time system, it would lock the center differential or transfer case and operate in the character of a part-time system.
If your Armada has an "Auto" mode, that's most likely the "AWD" mode in the paragraph above. Read your owners manual for more details, but in general, that's how most operate. It sounds like your Armada might have four modes, Auto, 4Hi, N, and 4Lo? In this case, Auto is to be used all the time. 4Hi uses the same drive ratio (1:1), but locks the center differential for more controlled torque and power output for snowy or dirt roads. 4Lo would use the gear reduction in the transfer case, typically 2-3:1, for deep snow or mud.
Typically, a part-time 4x4 system will have four modes: 2Hi, 4Hi, N, and 4Lo. But even in 2Hi, the front hubs are still "locked" meaning you are not seeing any fuel economy savings, because the entire front drivetrain is still turning.
Typically, full-time 4x4 systems have three choices, AWD, N, and 4Lo.
If your Armada has an "Auto" mode, that's most likely the "AWD" mode in the paragraph above.
My Suburban Full time had 4Hi, 4Hi locked, N and 4 Lo, don't remember if it had 4 Lo locked.
Locked front hubs.
But Part time systems have had Auto front hubs for some time, and do unlock to reduce drag. ( or manual hub on some older ones)
When I was researching my Pathfinder the LE had the Auto mode (simular to the Amarda?) and yes its a 2wd part time system that detects slip and engages 4wd until it not needed. As far as I could determine there is/was no center diff.
Hope this helps.
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1997 Sentra GXE w/195/50 15's and AD22VF, Tach, Halo's, Front seal, Rear SER Disc Brakes Soon to be sold
1997 S-ER 5 sp yea !!!
2003 Pathfinder SE 4WD
Ex- 2001 Sunny N16 RHD (N16 Nissan Bluebird Sylphy)
most truck based SUV's are part time RWD in auto mode, car based crossovers(pilot murano, element CRV rav 4 etc... and cars like audi are FWD until slipping(the exception the BMW 330xi id RWD until slipping as are mercedes)... and subarus ii believe are full time AWD not FWD first, but could be wrong...
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Quote:
Originally Posted by apachewoolf
pssst yo token . your not black any more...there is no man
most truck based SUV's are part time RWD in auto mode, car based crossovers(pilot murano, element CRV rav 4 etc... and cars like audi are FWD until slipping(the exception the BMW 330xi id RWD until slipping as are mercedes)... and subarus ii believe are full time AWD not FWD first, but could be wrong...
Yes Subaru's 4wd is full time
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1997 Sentra GXE w/195/50 15's and AD22VF, Tach, Halo's, Front seal, Rear SER Disc Brakes Soon to be sold
1997 S-ER 5 sp yea !!!
2003 Pathfinder SE 4WD
Ex- 2001 Sunny N16 RHD (N16 Nissan Bluebird Sylphy)
Linear Mode
