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2001 1500 hd 4wd my transfer case locks in and the front tires pull when its jacked up off the gruond but u can stop the front tire with your hand and the front drive shaft quits turning

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Posted on Jul 27, 2009

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Taking out transfer case in a 2001 gmc yukon

Posted on Sep 15, 2009

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My four wheel drive doesnt work on my isuzu rodeo. I used to hear the clicking in the center console and the transfer case. But now I dont hear anything. The switch use to work but now doesnt

does not work,means?
1: lamps in dash told me that
2: front axle dead, on ice?
3: FRONT Prop shaft dead, on ice or stands?
4: front prop ok,(spins but front axles is dead.
we cant guess what not works means.
this part time4wd, and only works on ice or dirt
its not TOD, nor AWD, like on say a Trooper.
its the old PT 4wd, and has strict rules for usage

ill pretend it fails on ice, below....

automatic or stick shift box? main?
this part time system is for iced roads or offroad
have you tested it off road yet? (or on iced over pavement?) Unlike TOD system (torque on demand)
also you can test it all out on jack stands.
lots of steps to that, do need all that. ?
any 4wd shop in town knows all the steps.
called hand testing 4wd. (part time 4wd)
what we do is make sure the the transfer case works
by hand,
then front axle left to right to center works.
I an also do this just front end off the ground,
is car automatic or stick shift. tests vary that
starting in 1996,the new front axle uses SHIFT on the FLy,part time 4wd, and can be tested on stands. Jack stands. got those>?

the front axle has vsv vacuum actuator(or elect motor)
that locks the front axle.
there are many systems of 4wd, and even Part time.
this one Vacuum, operated, and to test it
other than having vacuum pump like me (portable)
means you must have engine running to test it on stands. hint, lots more dangerous.
first i jackup whole car on stands x4
and put car in say 1st gear, or a/t in low.
AND MAKE SURE THE front prop shaft spins. at a distance , if yes the trans fer case works.
all 4 wheels spin, (no people or pets near car0
and someone in drives seat ,not you, for safety.
hand brake is off. (sure0
my guess now is the front wheels are dead.
back wheels must spin , if brakes drag, one will slower.. (oops another problem)
but front is dead, and so is the front actuator dead. the front prop shafts spins, but of the actuator is dead, the left axle unlocks.
to discover why, takes a vacuum pump
as no sane person would go under running engine with 2 live prop shafts. are you following me?

what i do is test the actuator with only left
wheel side on jack stands, right tire ground
the actuator is right there, see its vacuum diaphram casing, sure, see its vacuum nipple
i apply vacuum there.

engine off,
in 4wd, park (a/t) or m/t in 1st gear.
i apply say 10 inches of vacuum or more.
causes the actuator to move and the tire left locks up. (feel by hand turning tire)
the front prop shaft can not move. in this mode.
allowing me to test left front lock.
if spins free, the actuator is failing
if this locks, then the cars vacuum switches are failing. more tests.
im not going to document this part, (too long)

this is very simular to a jeep system with vacuum
other cars use a pressure pump there.
all versions of 4wd have different ways to test
in a shop.

why not go a 4wd shop. and get help
or any ASE shop in town?

that was the easy part.

the motor version, we hot wire the motor
to see it work.
using this drawingf466f86a-d30c-4316-b7f2-595c046540cf.jpg

unplug it first
hot wire the 2 pins,
always observe polarity
check voltage there in 4wd
if 12vdc there, then the controls are are working
and if yes,,you now know which pin is Plus.
my guess pin 4 is plus 12v
this step replaces vsv tests above.
its just an electric motor here.

the transfer case (frontprop shaft dead symptoms)
on this car it has motor too.
and a controller

the controller need the backup fuse good
then the transmission not in neutral,sends
12vdc power from neutral (not) goes to the controller to the motor drive controller
testing all this is tedious.
id check the motor there first on the transfer case.
mitchells has the drawings for all this.
see them now.

Jan 09, 2016 | 2004 Isuzu Rodeo

1 Answer

How do I know whether 4x4 is working?

that is part time 4wd
and i bet has manual locks on both front axle ends.
how'd i know that.???? grin
first off PT 4wd is for ICE or offroad
SO if NO ICE roads handly (i cant see you drive)
then go off road, or gravel road, or not pavement.
then shift to 4wd.
the rear will have power, for sure.
so that means how to test the front end
i do so on jack stands
put the car up on left side
engine off.
lock the front left lock and right.
now turn the left tire by hand,, bingo you cant.

if you can and the axle behind it does not spin that means the left lock is bad.
if the left axle does turns and so does the right axle , that means th right lock is bad.
3 tire on ground rules. part time.
the front drive shaft will not turn, if it does the transfer case is not in 4H or 4L. if the transfer case is working the rear drive shaft can not turn, in this test. (cuz both tires are on the ground)
see manual locking hubs test here and failure modes.

Nov 18, 2015 | 1987 Suzuki Samurai

1 Answer

Every thing work for my 4wd onvmy 2000 gmc z71 pickup the switxh actuators transfer case and diff but the front tires won't turn u can hear the transfer motor work and the actutor engagin but the front...

jack up front wheels turn a front wheel it should turn front drive shaft with 4wd engaged and the other wheel should turn backwards if it does that part is good if not possible broken axel

Feb 20, 2015 | GMC Cars & Trucks

2 Answers

I have a 56 plate jimny the fourwheel drive light is on on the dash is it stuck in fourwheel drive ?

Did you reverse more than 10 metres? Sounds like the hubs are locked into 4wd.this will work if you have auto hubs.but sometimes you have to turn the hub manually if they don't disengage.if you have gone some time or distance in 4wd

Dec 08, 2014 | 2006 Suzuki Jimny 1.5

1 Answer

1999 grand vitara 4wd how do front hubs disengage

best why is one tire on ground, front.! spin other tire. and feel prop by hand... fell the energy there. (there is no other way)
did you try to stop the prop shaft (xfr to axle) by and, while turning
tires? that is the test, free air spins only invite, fails reading due to
the viscous nature of GL5 lube.

the front axles has a 4wd drive has an internal pneumatic
air slave servo. and and external pump.
disconnect the air hose there. at pump to axle.
if axles is still locked up the internal slave is bad.


NOISE, is one of the most hardest problems to find in any machine
and for sure cars that only make noise moving, 100x harder
no body here can guess this, we are deaf here but I can tell you
most noises are:
1: bad u-joint.s
2: tires bouncing. (unbalances, did the silly glue on weights fall off?)
3: bad wheel bearing. (feel them, if you can feel play its bad)

use an electronic, stethoscope and end the danger, moving.

best bang for buck is here, buy cheap walfart head phone muffs for $5 for best play.

Sep 09, 2014 | 1999 Suzuki Grand Vitara

1 Answer

Transfer case troubleshooting

no year.????
what are tires touching , ice, nah, dirt? must we guess?????
its and offroad vehicle so we need that. data.
both front tires have zero torque? to the ground or what.?

you can check this out on jack stands.
put it in 4wd and make sure the front drive shaft spins, does it.>?
yes, good, no then transfer case
yes then front axle lock failure. the FSM covers all this.
my wanglers all have part time 4wd drive. not AWD.
so do the testing on dirt or damage the transfer case.
wind up is bad.
the car has no center differential. so do not drive it on pavement ice free. in 4wd. or bam, bad happens.

Jul 25, 2014 | Jeep Wrangler Cars & Trucks

1 Answer

4wd not engaging. Check actuator and seems to working properly. Jacked front end up and and when in 4wd the front tires spin freely. Any suggestions?

Does the driveshaft for the front wheels turn when in 4wd? The actuater might work but the diff lock for the front wheels might have broken. If the front driveshaft does not turn when in 4wd, the transfer case might be the problem.

Jan 02, 2014 | 2008 Chevrolet Silverado 2500HD

1 Answer

I have a huge loud knocking noise when i engage the 4wd on my 1999 navigator. i replaced the solinoid on the transfer case but it didnt stop. i thought it was maybe engaging the tranfer case 1/2 way.

I had a 4x4 year ago. Do you have front locking hubs ? I don't think so if you did I would ask if they were in or out. If there is nothing else It has to be coming from the transfer case. As far as I know no manufacture makes a true 4 wheel drive but Jeep except for maybe Raptor or Power Wagon. Most come with an open diff in the rear one wheel drive unless you order it special and the front you can't even order a locker if you wanted to 99.+% of 4x4s have open diffs in the front. Jack up one front wheel and one rear wheel if you didn't order a special rear end if you try to drive off the jacks you will sit there and spin your 2 wheel drive and not move.Ford says if you have worn tires or not the same air pressure in all tires it will do this. I think you have a bad u joint or pieces broken in the transfer case or it is out of adjustment. Jack car up like I said before and when the wheels spin without pulling it off the jack stands crawl under and see where the noise is coming from front or transfer case.I wonder if your shift motor could be bad they are about 65 dollars

Dec 16, 2011 | 1999 Lincoln Navigator

2 Answers

Transfer case wont engage

shift into 4wd and move truck a couple of feet.
if light is still off, park truck block the wheels set the park brake jack right front wheel and try to hand spin the wheel if wheel doesn't turn 4x4 is functioning properly but there is a wiring problem use an ohmmeter to check the 4x4 switch wiring fuse and bulb
if wheel turns freely the front axle or transfer case is not engaged
attempt to hand spin the front driveshft if the driveshaft will spin the transfer case is not engaged check the transfer case shift linkage, problem is in linkage or transfer case internals
if the driveshaft will not spin the transfer case is engaged properly
with trnsmission in neutral or park start engine measure vacuum on the two vac lines at front axle shift motor . one line should have approx 20" vacuum. other line should have none
if no vacuum measured look for vac leak or bad vac switch
if both lines have vac look for a bad vac swithc or ruptured cad actuator diaphragm
if one line has 20" +- VAC
move transfer case lever to 2wd measure vac again lines should have swapped vac signals
if no vac switch bad or 4wd shift likage needs adjusting
if yes vac motor bad or stuck or shift fork stuck
remove vac shift motor from the axle attach vac lines to shift motor engage disengage 4wd
does shift motor plunger move at least 1/2 inch
no shift motor bad
yes check axle shift fork and vac motor for binging

Jan 27, 2009 | 1999 Dodge Ram

2 Answers

4X4 not working

under the battey compartment is a lever that runs on vacume unhook the cable from the vacume plungger u will first have to take the battery and battery compartment out once u get the cable unhooked have someone start ur truck and then pull the cable under the battery box that goes to the 4x4 unit dont pull too hard u may pass up the sweet spot that locks in to 4x4 they may have to go to reverse to drive a couple of time while u r pullin on the cable itr will click forward bout a half inch when it locks in if ur 4x4 works after this u will need to replace the vacume plunger or do like i did and pull it till it locks in and tie it off to sumthin n go wheelin.... lol

Jan 05, 2009 | 1993 Chevrolet S-10 Blazer

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