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4x4 vacuum lines 2008 tahoe 5.3

There is oil coming out behind transfer case, Motor and transmission are clean. I did find a disconnected gas or vacum line that is cut or diconnected above that transfer case?

Posted by Anonymous on

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6 Suggested Answers

6ya6ya
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Posted on Jan 02, 2017

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BCally1
  • 133 Answers

SOURCE: 1995 dodge ram 1500 4wd, vacuum line

you sure its not the breather tube for the t-case. about 3/8 hose if it is. the vacuum lines for the 4x4 are small plastic lines. red, blue, yellow, etc. think there are four of them

Posted on Jan 10, 2009

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BCally1
  • 133 Answers

SOURCE: 1999 Dodge Ram 4X4 vacuum diagram

that line is just the breather tube for the tcase. the 4x4 vacuum lines are hard plastic lines that run from the tcase to the front axle disconnect

Posted on Jul 28, 2009

ZJLimited
  • 17970 Answers

SOURCE: I have a 96 Jeep

b1faf14.gif


1995-96 V-8 engine vacuum diagram-1997-98 V-8 engines similar; be sure to check the VECI label in the engine compartment

Also I have a GC, 1993, and I noted that besides maintaining a vent hose that is not going anywhere, just this subject with a ribbon next to the front suspension.

Hope helps (remember rated this).

Posted on Aug 12, 2010

Testimonial: "Well don't know if worked yet, but diagrams great! Thanks!"

KAComstock
  • 274 Answers

SOURCE: replaced shift motor on the

I myself have a 1999 Dodge Ram 1500 4x4. I feel your pain because i had the exact same problem when trying to replace the vacuum controlled shift mechanism. I myself am a mechanic and had a tough time finding why there was no vacuum so what did was replace the entire system with a Posi-Lock positive engagement system. I am not affiliated with Posi-Lock, i just know it works. Go to the link below and you will see the #400 system for about $200. This is great because it is mechanical and you will never worry about the failure prone vacuum system. If you put this on your truck you WILL NEVER have this problem again. I hope this helps you out!

www.4x4posi-lok.com/

Thank you!

Posted on Mar 30, 2011

  • 21 Answers

SOURCE: transfer case motor for push button 4x4

i have a 1993 blazer 4.3 w code 4x4 with a 4L60 E . my truck wouldn;t go in 4 hi or low. so i changed the transfer case motor and it works fine now. If you turn the ignition key to on but not crank the engine and open the driver door and push 4 hi button, you should hear the transfer case motor cycle for 3 or 4 seconds every time you push button and the light will flash until it goes in 4wd If the 4 hi button light doesn't flash during cycle then it could be a bad switch. if the transfer case motor won't cycle it could be a fuse or a bad transfer case motor . Hope this answers your question.
pgale89

Posted on Feb 08, 2013

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2 Answers

Got. A 2003 f150 4x4 got problems with 4 wheel drive locking in and stay in drive shaft turning front wheels not


Operationally vacuum shifts the front axle between 2WD and 4WD mode. The GEM ( Generic Electronics Module ) applies ground to the solenoid needed for the mode selected on the switch ( for ESOF ) or when the transfer case shift lever is moved ( MSOF ).The contact plates in the transfer case signal the GEM that the transfer case is engaged, and the Vacuum solenoids need to be activated ( either 2WD to 4WD or 4WD to 2WD ).

Lift and support the front of the truck so the front wheels are off the ground ( take safety precautions, chock wheels, jack stands, etc )
Key on, engage 4x4 and try to turn the front drive shaft.
- If it turns it is a problem with the transfer case.
- If it doesn't it is a front axle engagement problem ( this is what you seem to have, the transfer case is engaged and will drive the front shaft mine was a key on engine off test ).

- If the front drive shaft does not turn :
•With the truck running ( with front wheel back on the ground ), switch from 2WD to 4WD and back again, the vacuum shift motor should move the lever on the front axle.
sscullys_185.jpg
-- If the vacuum shift motor does not move:
1.Check for vacuum on the lines while shifting between modes. Pink vacuum line is 2WD mode, Light Blue vacuum line is 4WD.
2.Check the fuses for the 4WD system and the solenoids.
3.Check the vacuum lines from the vacuum shift motor to the solenoids on the firewall.
sscullys_187.jpg
4.Check the vacuum lines from the solenoids to the vacuum reservoir box behind the battery.
5.Check the vacuum reservoir box for cracks.
6.Typical solution is the vacuum lines ( to the solenoids or to the vacuum shift motor ) are cracked or the vacuum shift motor has a cracked diaphragm and has water in it.
7.Could be the shift plate contacts in the transfer case are corroded / not making good contact, and not activating the solenoids.
sscullys_186.jpg

Usually the case is cracked vacuum lines from the solenoids, the next common is a cracked vacuum reservoir box, and 1 time I have seen the mount for the vacuum disconnect motor broken ( motor floating free so it could not push against the axle )
sscullys_188.jpg

Aug 28, 2011 | 2003 Ford F150 Regular Cab

1 Answer

I can not get power to the motor to engage my front axle on my 4x4.


Power as in 12 V DC ? if yes, you are not in the correct area, the front axle is locked in and out of 4x4 mode with vacuum.

Operationally vacuum shifts the front axle between 2WD and 4WD mode. The GEM ( Generic Electronics Module ) applies ground to the solenoid needed for the mode selected on the switch ( for ESOF ) or when the transfer case shift lever is moved ( MSOF ).The contact plates in the transfer case signal the GEM that the transfer case is engaged, and the Vacuum solenoids need to be activated ( either 2WD to 4WD or 4WD to 2WD ).


Lift and support the front of the truck so the front wheels are off the ground ( take safety precautions, chock wheels, jack stands, etc )
Key on, engage 4x4 and try to turn the front drive shaft.
- If it turns it is a problem with the transfer case.
- If it doesn't it is a front axle engagement problem.

- If the front drive shaft does not turn :
•With the truck running ( with front wheel back on the ground ), switch from 2WD to 4WD and back again, the vacuum shift motor should move the lever on the front axle.
sscullys_200.jpg
Item #10 in this diagram
sscullys_10.gif
-- If the vacuum shift motor does not move:
1.Check for vacuum on the lines while shifting between modes. Pink vacuum line is 2WD mode, Light Blue vacuum line is 4WD.
2.Check the fuses for the 4WD system and the solenoids.
3.Check the vacuum lines from the vacuum shift motor to the solenoids on the firewall.
4.Check the vacuum lines from the solenoids to the vacuum reservoir box behind the battery.
5.Check the vacuum reservoir box for cracks.
6.Typical solution is the vacuum lines ( to the solenoids or to the vacuum shift motor ) are cracked or the vacuum shift motor has a cracked diaphragm and has water in it.
7.Could be the shift plate contacts in the transfer case are corroded / not making good contact, and not activating the solenoids.
sscullys_199.jpg

- If the front drive shaft turns:
For ESOF system
-- Check the fuses for the transfer case, engine compartment fuse panel, 17 & Cab fuse panel fuses 13 and 23 ( verify with owners manual, 97-97 & 99-03 MY can be slightly different on some items ).
-- Try hitting the transfer case with a dead blow hammer ( do not use a metal hammer, it can damage the transfer case ) to see if the transfer case shift motor is hung up .
-- Check the transfer case connector, to make sure the connector pins are clean and making good contact.
For MSOF systems
-- Check that the shift linkage on the transfer case is moving when the lever is moved from 2W to 4H and 4L.

Jul 30, 2011 | 2000 Ford F150 Flareside SuperCab

1 Answer

I got stuck in snow bank used my 4x4 and now it wont come out of 4x4


Take a look at the vacuum disconnect motor on the front axle ( picture below ) to see if it is trying to move. Item #10 in this picture

sscullys_6.gif

Close up
sscullys_110.jpg

IF this is not moving, could be :
1. The transfer case contact plates are not signaling the GEM ( Generic Electronics Module ) that the truck is changing mode from 4WD to 2WD. Check the connector on the side of the transfer case.
2. Vacuum is not being applied to the pink vacuum line on the vacuum disconnect motor ( 2WD mode, light blue is 4WD ). Check with a vacuum gauge that there is vacuum there.

Feb 02, 2011 | 1997 Ford F150 Regular Cab

1 Answer

2003 F-150 regular cab automatic transmission and the 4WD will not engage.


Operationally vacuum shifts the front axle between 2WD and 4WD mode. The GEM ( Generic Electronics Module ) applies ground to the solenoid needed for the mode selected on the switch ( for ESOF ) or when the transfer case shift lever is moved ( MSOF ).The contact plates in the transfer case signal the GEM that the transfer case is engaged, and the Vacuum solenoids need to be activated ( either 2WD to 4WD or 4WD to 2WD ).


Lift and support the front of the truck so the front wheels are off the ground ( take safety precautions, chock wheels, jack stands, etc )
Key on, engage 4x4 and try to turn the front drive shaft.
- If it turns it is a problem with the transfer case.
- If it doesn't it is a front axle engagement problem.

- If the front drive shaft does not turn :
•With the truck running ( with front wheel back on the ground ), switch from 2WD to 4WD and back again, the vacuum shift motor should move the lever on the front axle.
{ picture of shift motor }
-- If the vacuum shift motor does not move:
•Check for vacuum on the lines while shifting between modes. Pink vacuum line is 2WD mode, Light Blue vacuum line is 4WD.
•Check the fuses for the 4WD system and the solenoids.
•Check the vacuum lines from the vacuum shift motor to the solenoids on the firewall.
•Check the vacuum lines from the solenoids to the vacuum reservoir box behind the battery.
•Check the vacuum reservoir box for cracks.
•Typical solution is the vacuum lines ( to the solenoids or to the vacuum shift motor ) are cracked or the vacuum shift motor has a cracked diaphragm and has water in it.
•Could be the shift plate contacts in the transfer case are corroded / not making good contact, and not activating the solenoids.
sscullys_111.jpg

- If the front drive shaft turns:
•For ESOF system
-- Check the fuses for the transfer case, engine compartment fuse panel, 17 & Cab fuse panel fuses 13 and 23 ( verify with owners manual, 97-97 & 99-03 MY can be slightly different on some items ).
-- Try hitting the transfer case with a dead blow hammer ( do not use a metal hammer, it can damage the transfer case ) to see if the transfer case shift motor is hung up .
-- Check the transfer case connector, to make sure the connector pins are clean and making good contact.
•For MSOF systems
-- Check that the shift linkage on the transfer case is moving when the lever is moved from 2W to 4H and 4L.

Jan 10, 2011 | 2003 Ford F150 Regular Cab

1 Answer

I have a 98 f150 4x4 automatic with the 4x4 shifter on the floor. Wheni shlift into 4x4 the front does not go in to gear.


Lift and support the front of the truck so the front wheels are off the ground ( take safety precautions, chock wheels, jack stands, etc )
Key on ( engine off ), engage 4x4 and try to turn the front drive shaft.
If the front driver shaft turns it is a problem with the transfer case.
If it doesn't it is a front axle engagement problem.

The front axle engagement problems are either rotten vacuum lines from the shift motor solenoids or the vacuum disconnect motor.
The vacuum disconnect motor ( Item #10 )
sscullys.gif
Close up of what it looks like :
sscullys_5.jpg

The vacuum lines run to the solenoids
sscullys_6.jpg

The Pink Vacuum line is the 2WD operation, the Light blue vacuum line is the 4WD operation. You can confirm the operation by applying vacuum at the solenoid, and the Vacuum disconnect motor should move.
If this tests good, check that there is not a crack in the vacuum reservoir behind the battery. The reservoir runs past the check valve ( that is to the intake I seem to recall ) and to a T to both solenoids. If the reservoir is cracked, it cannot supply vacuum to the solenoid and while it is operating correctly, the vacuum is not there to operate the disconnect motor.

The solenoids always have + DCV at them, the GEM controls them by applying ground to the solenoids.

Start by checking the front driver shaft, and work from there. If the front drive shaft spins, you have an issue in the transfer case, that is mechanical ( manual Shift on the Fly - could be hung up. you can try a dead blow hammer on the back of the transfer case, while trying to shift in and out of 4WD. Just be cautious that you do not damage the transfer case by hitting it too hard, too much or with a metal hammer ).

Nov 02, 2010 | 1998 Ford F150 Regular Cab

1 Answer

My 2003 F-150 will not engage the 4-wheel drive when the switch is turned on? Two days ago it worked fine and the light does come on?


Lift and support the front of the truck so the front wheels are off the ground ( take safety precautions, chock wheels, jack stands, etc )
Key on, engage 4x4 and try to turn the front drive shaft.
If it turns it is a problem with the transfer case.
If it doesn't it is a front axle engagement problem.

I am going to guess the drive shaft will not turn, and the problem is the shift disconnect motor on the front axle, or the shift solenoids.
The shift motor looks like this
37bcd6a.jpg

The shift solenoids look like this :
1a11fc1.jpg

You can check the shift solenoids with a vacuum gauge. The blue vacuum line is the 4WD operation, the pink is the 2WD operation. Pull the vacuum line at the shift disconnect motor, and install the vacuum gauge. Shift into 4WD and the vacuum should be on the line, and hold. If not could be the disconnect motor or the vacuum line to the motor.

Could also be the shift motor in the transfer case, but with the 4x4 light on the cluster lighting up, the transfer case should have shifted, the confirm comes from the transfer case to illuminate the 4x4 indicator on the cluster.

Feb 20, 2010 | 2003 Ford F150 Regular Cab

2 Answers

4wd does not work


Electronic Shift On the Fly (ESOF) Operation
The ESOF system is an electronic shift 4x4 system that allows the operator to choose between two different 4x4 modes as well as 2-wheel drive. The operator can switch between 2WD and 4WD HIGH mode at speed. To engage or disengage LOW Range, the vehicle speed must be less than 5 kph, the brake depressed, and the transmission must be in NEUTRAL.

The transfer case is equipped with an electromagnetic clutch which is located inside the case. This clutch is used to spin up the front drive-line when shifting from 2WD to 4x4 High mode at speed. When the control switch on the instrument panel is turned, the generic electronic module (GEM) recognizes that a shift has been requested and activates the electromagnetic clutch and the relays which power the transfer case shift motor. When the shift motor reaches the desired position as determined by the contact plate position inputs to the GEM, power to the shift relays and motors will be removed. When the transfer case front and rear output shafts are synchronized, the spring loaded lockup collar mechanically engages the main-shaft hub to the drive sprocket. Finally, the front axle collar is engaged and the electromagnetic clutch is deactivated.

Shift Between 2WD and 4x4 HIGH:
Shifts between 2WD and 4x4 HIGH can be made at speed. Listed below are the inputs and outputs needed by the GEM to execute a change between any of these modes.

Feature Inputs:
*4WD Mode Switch (Various resistances).
*Contact Plate Position Inputs A, B, C, D (grounded when closed, open circuit when open).

Feature Outputs:
*4x4 Shift Motor Relay Outputs
*Transfer Case Clutch Relay (grounded when relay is on, open circuit when relay is off).
*4x2/4x4 Vacuum Solenoid (grounded when activated, open circuit when deactivated).
*Cluster Indicators (ground when activated, open circuit when deactivated).

Shifting Into/Out of 4WD LOW:
When shifting into or out of 4WD LOW, the GEM requires that the vehicle speed be less than 5 kph, the brake is applied, and the transmission is in NEUTRAL.

Feature Inputs:
*4WD Mode Switch (Various resistances).
*Contact Plate Position Inputs A, B, C, D (grounded when closed, open circuit when open).
*VSS Sensor (Sinusoid Signal: 0.7V-20V, 2.2 Hz/mph).
Brake Input (battery voltage when brake is depress, open circuit when not activated).
*Transmission Range Sensor (grounded when transmission is in NEUTRAL, open circuit otherwise).
8Start/Clutch Depressed Input

Feature Outputs:
*4x4 Shift Motor Relay Outputs
*4x2/4x4 Vacuum Solenoid (grounded when activated, open circuit when deactivated).
*Cluster Indicators (grounded when activated, open circuit when deactivated).

4WD Mode Switch
A rotary switch allows the vehicle operator to choose between 2WD, 4WD HIGH, and 4WD LOW modes of 4x4 operation.

GEM Module
The Generic Electronic Module (GEM) controls the operation of the 4x4 system

Vehicle Speed Sensor
The vehicle speed sensor (VSS), mounted in the rear of the transfer case, informs the GEM of the vehicle speed.

Transfer Case Shift Motor Sense Plates

The shift motor sense plate, an integral part of the electric shift motor, informs the GEM to the positions of the transfer case

Transmission Range Sensor
Located on the left side of the transmission, this sensor informs the GEM when the transmission is in the NEUTRAL position.

Electric Shift Motor
The electric shift motor, mounted externally at the rear of the transfer case, drives a rotary cam which moves the mode fork and range fork within the transfer case to select between the 2WD, 4WD HIGH, and 4WD LOW positions.

4x4/4x2 Vacuum Solenoids
These two solenoids are attached to the upper RH side of the engine compartment dash, and alternately route vacuum to the vacuum motor which engages/disengages the center axle disconnect collar in the front axle assembly.

4x4 Shift Motor Relay
A module containing two relays which under the control of the GEM, shift the transfer case shift motor between the 2WD, 4WD HIGH, and 4WD LOW modes.

Transfer Case Clutch Relay
An electromechanical relay is used to activate the transfer case clutch within the transfer case.

Good luck and hope this helps,but start with the simple and check the fuses and wire harness. Both white/light blue stripe wires should have 12V in run. The GEM will ground the left side (closest to engine) solenoid to disengage the front axle. It will ground the the right side solenoid (closest to fender) to engage the front axle. If the GEM doesn't see Neutral it will not let the truck come out of 4Lo. If the GEM had water leaking on it it may well be the root of the problem. The shift motor only has power when the GEM sends it a signal to move the shift lever. Once the shift is completed the motor shuts off. There are 2 wires that control the shift motor. A yellow and an orange. The GEM alternates between 12v and Ground to these wires to control which way the motor turns. The GEM uses the transfer case shift relay module to control the power to the motor. There are contact plates inside the shift motor assembly that indicate the position that the shift lever is in. This is what the GEM used to know what the T-case is doing. Any one of these components can fail.







Jan 10, 2010 | 2002 Ford Explorer

1 Answer

What spec oil is used in the transfer case of a 1996 chev tahoe


The transfer case shows to use Automatic Transmission Fluid. I would personally use a full synthetic transmission fluid as well. I showed three transfer case options for that vehicle and depending on which one you have it will hold anywhere from 1.5 quarts to just a little over 2 quarts depending on which one you have.


Jan 02, 2009 | 1996 Chevrolet Tahoe

3 Answers

Transfer case motor for push button 4x4


i have a 1993 blazer 4.3 w code 4x4 with a 4L60 E . my truck wouldn;t go in 4 hi or low. so i changed the transfer case motor and it works fine now. If you turn the ignition key to on but not crank the engine and open the driver door and push 4 hi button, you should hear the transfer case motor cycle for 3 or 4 seconds every time you push button and the light will flash until it goes in 4wd If the 4 hi button light doesn't flash during cycle then it could be a bad switch. if the transfer case motor won't cycle it could be a fuse or a bad transfer case motor . Hope this answers your question.
pgale89

Dec 16, 2008 | 1994 Chevrolet S-10 Blazer

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