My 4WD will not engage why?

Tiny
DPAIK
  • MEMBER
  • 1999 DODGE RAM
  • V8
  • 4WD
  • AUTOMATIC
  • 155,095 MILES
The 4wd won't engage. The indicator light on the dash does not come on. I serviced the front drive shaft last summer and test drove it after installation and it worked then.
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Sunday, November 30th, 2008 AT 7:08 PM

37 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,014 POSTS
Hi:
I need you to check the linkage to the transfer case to make sure it's working properly. Also, check all vacumn lines to and from the transfer case, axle.
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Tuesday, December 9th, 2008 AT 9:33 AM
Tiny
DPAIK
  • MEMBER
  • 2 POSTS
The linkage seems fine. When I put the lever in the 4hi position and give some gas, I can feel the lever move/vibrate. The vacuum line appear okay. There is one large line coming from the front actuator which appears to have been cut and wire-tied with an open end. BTW my 4wd has worked in the past with everything the way it is now. Thanks.
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Tuesday, December 9th, 2008 AT 12:58 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,014 POSTS
Check to see if there is vacuum at the cut hose. If so, replace it.
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Tuesday, December 9th, 2008 AT 1:21 PM
Tiny
SKELLEYTAZZ
  • MEMBER
  • 1 POST
  • 1999 DODGE RAM
  • V8
  • 4WD
  • AUTOMATIC
  • 136,000 MILES
I have a 4x4 ram and just had the transmission rebuilt. I didn't notice till winter driving that when I try to shift into 4 wheel drive high on the floor it won't budge. I doesn't grind or try to shift it dead heads. I can stop and shift into 4 low fine. But on the go it won't go into 4 high?
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Tuesday, May 11th, 2021 AT 12:28 PM (Merged)
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
I would go back to the tranny installer and see if the misadjusted anything. The only thing you can do without disassembly is adjust the shift linkage. Here's how:
SHIFT LINKAGE 1. Move shift lever to 2H position. Raise and support vehicle. Loosen shift rod lock bolt at trunnion on linkage. Ensure shift rod does not bind in linkage trunnion. Re-check that transfer case shift lever is in 2H position (second position from full forward). 2. Lower vehicle. Position shift lever in cab so distance from instrument panel to 2H position dot in shift lever insert in 5.75" (146 mm). Ensure measurement is made parallel to floor of vehicle. Tighten shift rod lock bolt to 90 INCH lbs. (10 N.M). Check shift and linkage operation in all ranges. Readjust as needed.
WILL NOT SHIFT OR DIFFICULT TO SHIFT INTO GEAR Vehicle speed too high; slow vehicle and attempt shift. Vehicle has been operated in 4H mode too long on dry surface; stop vehicle, place transfer case in Neutral to relieve driveline preload torque. Ensure transfer case external linkage is not binding. Ensure correct fluid is used. Internal parts may be worn or damaged.
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Tuesday, May 11th, 2021 AT 12:28 PM (Merged)
Tiny
MYZ92
  • MEMBER
  • 4 POSTS
  • 1999 DODGE RAM
  • V8
  • 4WD
  • AUTOMATIC
  • 120,000 MILES
The transfer case has 2 vacuum tubes coming out of the side going to the front hub locker and there is no vacuum going to either of them and they are cut off at the transfer case. The key on the top of the case only has vacuum going to one of the tubes no matter whether it is in 2 or 4 wheel drive. What I am getting at is the truck does shift into 4 wheel drive but the light on the dash does not come on and it shifts with the transfer case but the front wheels dont turn and there is no vacuum going to the slider at all, before all this was happening the 4x4 light was blinking randomly but it would stop if I hit the brake or slowed down. If you have any diagrams it would help alot or anything if you've seen this before at all, im a mechanic but I cant figure this out
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Tuesday, May 11th, 2021 AT 12:28 PM (Merged)
Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Heres the vacuum diagram for the t-case controls.Be sure it is all hooked up properly


https://www.2carpros.com/forum/automotive_pictures/1639_dodge1_2.jpg

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Tuesday, May 11th, 2021 AT 12:28 PM (Merged)
Tiny
CARLSP
  • MEMBER
  • 32 POSTS
  • 1998 DODGE RAM
  • 5.2L
  • V8
  • 4WD
  • AUTOMATIC
  • 220,000 MILES
It did work before. When I put it 4Hi or 4Lo then 4x4 light will come saying that it is engaged but it is not. I have replaced the front axle actuator and housing that has the sleeve that connects my front drive axles when in 4WD. I have checked the vacuum for both 2WD and 4WD and it is around 19 inch Hg. Like I said when I put it in 4WD the actuator does slide over and active the engage light and I have removed it twice to make sure that the fork and sleeve are lined up correctly. I am at a loss now and could really use a idea. Thanks.
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Tuesday, May 11th, 2021 AT 12:28 PM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,554 POSTS
Hello,

It sounds like the shift fork bushings have worn not moving the fork completely. Here is an exploded diagram so you can see what I am talking about. I would see if you can manually move the shift arms to see if you can get it to work. Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.
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Tuesday, May 11th, 2021 AT 12:28 PM (Merged)
Tiny
CARLSP
  • MEMBER
  • 32 POSTS
Thanks so much for the insight, much appreciate it. That does make sense. Just to be clear, are we talking about the mode fork, part number 49 or the range fork, part number 53 in the first image, 231 transfer case? I would guess the mode fork but want to be sure. I will tearing it apart this weekend and will let you know the results. Thanks again.
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Tuesday, May 11th, 2021 AT 12:28 PM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,554 POSTS
When you have it apart look at both forks I would replace all plastic ride retainers if they look worn or brittle. Can you please shoot a quick video with your phone so we can see what's going on, that would be great. You can upload it here with your response.
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Tuesday, May 11th, 2021 AT 12:28 PM (Merged)
Tiny
KEVIN228670
  • MEMBER
  • 2 POSTS
  • 1998 DODGE RAM
  • 189,000 MILES
I have a 1998 dodge ram 1500 4x4. Has 5.2 in it automatic. The 4wd isn't working but the front drive shaft spins. Also, it don't seem to have the power it should. I've replaced the plugs, cap, and button and its still the same. It seems to miss bad when it goes uphill.
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Tuesday, May 11th, 2021 AT 12:28 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Is the light indicating at 4WD? Scan the TCM/Computer for code/s if any present post them-

Check vacuum at axle shift motor

AXLE SHIFT MOTOR FUNCTIONAL TEST
Raise and support the vehicle. Disconnect the vacuum harness from the axle shift motor and connect a vacuum pump to the vacuum shift motor front port. See Fig. 2.
Apply 15 in. Hg (51 kPa) of vacuum to the front port and rotate left front wheel to fully disengage the inner and intermediate axle shafts (i.E, shift to two-wheel drive operation).
The shift motor should maintain the vacuum applied to the front port for a minimum of 30 seconds. If the motor does not maintain the vacuum, replace it. If the motor does maintain the vacuum, proceed to the next step.
Disconnect the vacuum pump from the vacuum shift motor front port. Connect the vacuum pump to the vacuum shift motor rear port, cap the port for the 4WD indicator lamp switch, apply 15 in. Hg (51 kPa) of vacuum to the rear port.
The shift motor should maintain the vacuum applied to the rear port for a minimum of 30 seconds. If the shift motor does not maintain the vacuum, replace it. See AXLE SHIFT MOTOR under REMOVAL & INSTALLATION. If the motor does maintain the vacuum, proceed to the next step.
Remove the cap from the port for the 4WD indicator lamp switch. If vacuum was present, the shift motor is functioning normally. If vacuum was not present, go to next step.
Apply 15 in. Hg (51 kPa) of vacuum to the shift motor rear port. Rotate the left front wheel as necessary and ensure that the inner and intermediate axle shafts are completely engaged. The axles must be completely engaged (i.E, shifted to 4WD operation) to open the port for the 4WD indicator lamp switch.
Determine if vacuum is present at the port for the 4WD indicator lamp switch again. If vacuum was present at the port, the shift motor is functioning normally. If vacuum was not present at the port, replace the shift motor. See AXLE SHIFT MOTOR under REMOVAL & INSTALLATION.
Connect the vacuum harness to the shift motor. See VACUUM HOSE ROUTING. Remove the supports and lower the vehicle.
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Tuesday, May 11th, 2021 AT 12:28 PM (Merged)
Tiny
KEVIN228670
  • MEMBER
  • 2 POSTS
The 4wd light does not come on.
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Tuesday, May 11th, 2021 AT 12:28 PM (Merged)
Tiny
DIANESUPTON
  • MEMBER
  • 1 POST
  • 1998 DODGE RAM
  • V8
  • 4WD
  • AUTOMATIC
  • 16,493 MILES
Not sure exactly how to put the truck into 4 high. Do I stop and put it in park then put it in 4 wheel drive. Put it in neutral then in 4 wheel drive and then back it up a bit to kick it in or do I do this while driving? Also when it is in 4 wheen drive it makes a little quiet humming noise. Is that normal and sometimes when I turn the wheel when its in 4 wheel drive the truck will hop. Does that mean it isn't all the way in?
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Tuesday, May 11th, 2021 AT 12:28 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,014 POSTS
You should have shift on the fly 4wd. That means you can shift into 4wd when you are moving at a slower speed. You can take it out of 4wd the same way.

As far as the noise, that is normal. You hear the transfer case and the front differential being engaged. Nothing to worry about.

Now for the hop you experience. DO NOT USE 4wd on a dry surface where the tires can get good traction. If you do, the steering will fight you, it will hop, and eventually cause damage to the 4wd system. Only use it when the conditions justify it such as snow, ice, mud, any condition that would allow the tires to spin.

Let me know if you have other specific questions.

Joe
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Tuesday, May 11th, 2021 AT 12:28 PM (Merged)
Tiny
MICHAEL BALLARD
  • MEMBER
  • 1 POST
  • 1997 DODGE RAM
  • 5.9L
  • V8
  • 4WD
  • AUTOMATIC
  • 160,000 MILES
No light on dash and four wheel drive won't engage. Shifts thru 2hi to 4hi to 4lo okay will not engage.
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Tuesday, May 11th, 2021 AT 12:29 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,014 POSTS
Hi and thanks for using 2CarPros.

Most often, the shift linkage between the shifter and the transfer case either comes apart or comes loose and goes out of adjustment. That is where I would recommend you start.

Park on a level surface, place the parking brake on, place the vehicle in park, and block the wheels so the vehicle can't move. Craw under the vehicle and locate the transfer case. Locate the linkage (see picture 1) and conform that it hasn't come disconnected on either end (held in with a plastic clip on both ends) and make sure the adjuster bolt didn't come loose allowing the linkage to move without changing the transfer case shift lever.

If you find the linkage has come off, you can purchase just the plastic clips or you can purchase the entire linkage aftermarket.

Here are the adjustment directions:

______________________________________________________

ADJUSTMENTS
1. Move shift lever into 2H position.
2. Raise vehicle.

3. Loosen shift rod lock bolt at trunnion.
4. Check shift rod fit in trunnion. Be sure rod does not bind in trunnion.

5. Verify that transfer case shift lever is in 2H position.
6. Tighten shift rod lock bolt to 10 Nm (90 inch lbs.) Torque.
7. Lower vehicle.
8. Check shift linkage operation. Be sure transfer case shifts into and operates properly in all ranges.

_____________________________________________________

Let me know if this helps or if you have other questions.

Take care,
Joe
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Tuesday, May 11th, 2021 AT 12:29 PM (Merged)
Tiny
JAGERBOMBS192
  • MEMBER
  • 1 POST
  • 1997 DODGE RAM
  • 151,000 MILES
I have a problem with my 4 Wheel Drive engaging and disengaging. It also seems like with the front end binds up and pops while turning. When im driving the front end binds on a snowy road and it sounds like theirs a popping noise coming from the front end too. The 4 wheel drive takes a very long time to engage to and disengage I dont know why it does. Can you please help with these problems? From the ring and pinon to the driver side. And yes I have checked everything and replaced
all of the tierods.
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Tuesday, May 11th, 2021 AT 12:31 PM (Merged)
Tiny
RIVERMIKERAT
  • MECHANIC
  • 6,110 POSTS
The transfer case actuator motor should fix the problem here is a diagram below to show you how to replace it.
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Tuesday, May 11th, 2021 AT 12:31 PM (Merged)

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