All time 4WD doesn't engage

(what to does that mean) 4whl drv.
4H, part, 4H full, or 4L?????????
1: the lamps read wrong.
2; the front is dead on ice,rear slips and front dont pull?
3: on jackstands doing tests.?
4: off road. i see the front is is dead.?
??????????????????????????????
if this the Full time or part time system. (option)
if part time, its not for dry pavement, its for ice or off road.
if full time 4wd, then long answer. (pending what you have)????

if you are just trying to fix a part time system. front axle dead.?
then test the vacuum servo there. (command trac)
but on newer jeeps that part is gone, and the front axle
is driven or not from the transfer case.
did you scan the PCM first and check fuses,? see if you have DTC errors related to 4wd?


here ill quote the wiki
The Liberty is available with either a part-time Command-Trac or full-time Selec-Trac transfer case.

the diagnosis is totally different on each.
command track is part time. do not use on dry icefree pavement in 4wd modes.

The Selec-Trac transfer case has five positions: 2-HI, 4-HI Part-Time, 4-HI Full-Time, Neutral, and 4-LO.
got this?????

in above do not use part time on dry pavement.
only dirt or ice . period.

what does engage mean.? it fails on ICE or DIRT

engaged, means, (mechanically) one tire front and rear have traction

with LSD front and rear all 4 have traction and spin on ice

does it?

part time 4wd dont work on dry pavement so that is my 1st question

why not state, what you are driving on, and what does engage means

by what means did you check engaged.????



this car is not AWD, do you know the difference from AWD and

Part time 4wd? the diff, is there is center differential. on part time

so must be (true test) tested on ice, or dirt.



see the videos here, or a demo.

or on ice. ice you will see front and rear both working,

on dry plave ment all you get is windup... very very bad to do

in traffic, causing you to wreck and other to get , hurt.

if you understand all that, then do say what you mean

ENGAGED.

if you know what windup is and it dont, then you are correct

its not engaged. (jack left front tire up, engage it and feel it? by turning the the tire, it must fight you)

front up, rear down. in 4wd.

here it it is again.

http://www.fixkick.com/part-time-test.html



if it dont engage for real,. may i introduce you to the FSM

its in my hand now.

page 3B-3 . see it?

switch closes in xfr case

ECU sees that and powers up the air pump.

if pressure is good the Ecu is told that, if wrong you get scanned DTC code saying just that (obd2 scan too)

the pump has 2 shut off modes, good pressure. and fails to hold for 10seconds. (prevents pump from running all time)

if all the above works the Lamp glow by PCM command.

if you have full pressure , the lock in the front axle is now locked

no pressure, no lock yes full pressure it must lock or the axle

actuator is bad.

the page 3B6 says pressure is 4.25 to 6.40

page 3b10 is the acutator test. and the TRUE ENGAGE TEST

front wheels off ground.

apply 4.2psi with shop air and reg.at the acutator nipple

1: you spin one tire, the other spins backwards (GOOD test)

kill the 4.2 psi supply air

2: you spin one tire.

and the other tire, does nothing, (remains stationary)

pass. test 2.



test one is locked

test 2 is 2wd.



the other tests are on ice or dirt.

does that help?

Check the oil in the transfer case. If it has lots of metal in it... time for a new one. They aren't the world's strongest.
Another check: Lift the front of the truck, while keeping the rear wheels on the ground. Engage the 4x4 switch (then turn the truck off) crawl under and try to turn the front driveshaft by hand. If it turns and the wheels turn, the transfer case is the problem if it turns but the front wheels don't... front diff issues. Any grinding, crunching etc is also a clue.

check operation of vacuum diaphragm under battery that actuates 4WD cable

On these issue, there are few solved help links for troubleshooting the issue easily.-------

Click the link below: ---

No 4x4 light on dash?

http://repairhelpcenter.blogspot.com/2011/12/no-4x4-light-on-dash.html

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4X4 Truck makes roaring noise in the front end?

http://schematicsdiagram.blogspot.com/2012/01/4x4-truck-makes-roaring-noise-in-front.html

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Car will not go into 4WD high or 4WD low?

http://schematicsdiagram.blogspot.com/2011/12/car-will-not-go-into-4wd-high-or-4wd.html

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No 4x4 light on dash?

http://repairhelpcenter.blogspot.com/2011/12/no-4x4-light-on-dash.html

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4 wheel drive system will not disengage?

http://technoanswers.blogspot.com/2012/01/4-wheel-drive-system-will-not-disengage.html

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4WD light is flashing and beeping? NO 4WD high?

http://schematicsdiagram.blogspot.in/2012/02/4wd-light-is-flashing-and-beeping-no.html

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2002 Jeep Wrangler: 4WD Idiot Light is ON?

http://technoanswers.blogspot.in/2012/06/2002-jeep-wrangler-4wd-idiot-light-is.html

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Traction control switch will not engage on 4WD High or Low

http://whoisbyme.blogspot.com/2012/10/traction-control-switch-will-not-engage.html

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4WD light flashing and 4WD will engage after few minutes

http://repairhelpcenter.blogspot.com/2012/10/4wd-light-flashing-and-4wd-will-engage.html

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2008 Toyota Tundra: 4x4 Wheel Drive Light is Flashing?

http://technoanswers.blogspot.in/2012/05/2008-toyota-tundra-4x4-wheel-drive.html

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4x4 front differential will not engage the axle on ford?

http://technoanswers.blogspot.in/2012/02/4x4-front-differential-will-not-engage.html

-------

4x4 will not engage on Ford F150?

http://technoanswers.blogspot.in/2012/02/4x4-will-not-engage-on-ford-f150.html

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Dodge Ram 4x4 light keeps flashing

4X4 LOW LIGHT IS FLASHING ON DASH

http://technoanswers.blogspot.in/2012/09/dodge-ram-4x4-light-keeps-flashing.html

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Ford 4x4 front wheels will not engage?

http://technoanswers.blogspot.in/2012/02/ford-4x4-front-wheels-will-not-engage.html

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These details will help.

Thanks.

The actuator under the battery runs the engagement of the front Diff .If 4 - wheel low is working and high is not then that is a linkage adjustment problem at the transfer case or a internal problem with in the transfer case not the transmission . Those transfer case are not that expensive from a salavage yard if that ends up being your problem and they are not that hard to change ... Alot easier then the transmission

i've been told it was the 4wd actuator located on the passenger side near were the cv joint goes in to the front axle a good test is to floor jack it up so both wheels are off the ground and have someone on the other side , put in nutrual turn both wheels one way at same time and the 4wd drive shaft should turn if not its your actuator, costs about $86 for anew actuator and takes about 5 mins to change once you have the tire off

The Lo is working properly by requiring to put it in neutral but are you sure the front wheels spin? I would first check the 4wd actuator on the front diff & make sure thats working. You will need 2 people for this. One laying under the diff & watching/listening and the other pushing the buttons

It sounds like your driveline to the rear wheels is broken. Could be transfer case output shaft to the rear wheels has broken. Try disconnecting the rear drive shaft and see if you can turn it by hand with the transfer case engaged in 2WD. If you can turn it while the Sahara is in gear, the output shaft is no longer connected to the engine for some reason.

I work for Toyota, and I will be glad to provide you with the actual answer:

The RAV/4 product is available in two models, a 4WD model and a 2WD model.
The difference between the two is on the 2WD model, there is no driveshaft going under the vehicle to the rear wheels, and no rear differential. There is no "RAV/2"; both models are called RAV/4's.

There is a lot of common confusuion about how the 4WD works. It is full time 4WD. In other words, it is always in 4WD. It does not "kick in/kick out/automatically engage", or anything like that. It is 4WD all of the time. But, when I say "4WD", that is sometimes mistaken for "all wheel drive", and, in this case, the RAV/4 is not "AWD". What this means is that if you raise the RAV/4 up on a lift, and put it in gear, 1 rear and the other side front tires will spin. True "all wheel drive" would have ALL 4 wheels spinning. This is not the case with the Rav/4. What the RAV does have, making up for not having "True AWD" on the 5 speed model, however, is a switch that locks the center differential in the transfer case, which, when engaged, applies a method of "locking" the 4WD system for maximum traction, but it is still not AWD. The automatic version doe not have this ability.
The last "true AWD" vehicle for purchase was a 1970's International Scout.
If you are considering purchasing a RAV/4, that is a very good investement. They hold their value quite well, and are virtually bulletproof; I do not make any "money" off my RAV/4 customers...
Just "gas station work". Very nice cars. I hope that this helps you, please feel free to comment back with any otherr questions...Glad to be of assistance.
Toyota Ed