4x4 not engaging
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From: TN (423)
4x4 not engaging
Ok I know I read on here somewhere about how to check the 4wd but I have been searching for a couple hours with no luck.
Here is my problem. I bought the truck a couple weeks ago and the 4wd was fine. Now its not going into gear. The light is not coming on the dash. But as im shifting through the t case i can feel it moving between gears and can make it grind a little. Makes me think the shifter is indeed moving betwen gears its just not engaging.
I read somewhere it could be something to do with the vaccum lines. How do I test this? What parts am I looking at having to replace and whats the cost?
If its gonna be to much im considering just dropping the front driveshaft and saving me some mpg.
Here is my problem. I bought the truck a couple weeks ago and the 4wd was fine. Now its not going into gear. The light is not coming on the dash. But as im shifting through the t case i can feel it moving between gears and can make it grind a little. Makes me think the shifter is indeed moving betwen gears its just not engaging.
I read somewhere it could be something to do with the vaccum lines. How do I test this? What parts am I looking at having to replace and whats the cost?
If its gonna be to much im considering just dropping the front driveshaft and saving me some mpg.
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Joined: Jul 2006
Posts: 12,204
Likes: 10
From: Gainesville, Ga.
read this.
http://dodgeram.org/tech/repair/4X4/4x4_engagment.htm
its easy to test, diagnose, repair.
front driveshaft does not turn in 2wd, so there's no mpg savings to be had by removing it. sorry.
if/when you get tired of fixing the cad, look into a posilok cable.
http://dodgeram.org/tech/repair/4X4/4x4_engagment.htm
its easy to test, diagnose, repair.
front driveshaft does not turn in 2wd, so there's no mpg savings to be had by removing it. sorry.
if/when you get tired of fixing the cad, look into a posilok cable.
Thread Starter
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Professional
Joined: Dec 2009
Posts: 203
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From: TN (423)
read this.
http://dodgeram.org/tech/repair/4X4/4x4_engagment.htm
its easy to test, diagnose, repair.
front driveshaft does not turn in 2wd, so there's no mpg savings to be had by removing it. sorry.
if/when you get tired of fixing the cad, look into a posilok cable.
http://dodgeram.org/tech/repair/4X4/4x4_engagment.htm
its easy to test, diagnose, repair.
front driveshaft does not turn in 2wd, so there's no mpg savings to be had by removing it. sorry.
if/when you get tired of fixing the cad, look into a posilok cable.
thanks for the link
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Professional
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From: TN (423)
Originally Posted by dodgeram.org
If this truck was mine I would:
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: continue...
Attempt to hand spin the front driveshaft If the driveshaft WILL spin, the transfer case is not engaged Check the transfer case shift linkage, problem is in linkage (or in the tran$fer ca$e internal$ <-- yes this means $$, ouch!)
If the driveshaft will NOT spin, the transfer case is engaged properly: continue...
USE CAUTION! With transmission in neutral or park, start engine, measure vacuum on the two vac lines at front axle shift motor. One line should have approx 20" vacuum, other line should have none.
If NO vacuum measured, look for vacuum leak or bad vacuum switch.
If both lines have vacuum, look for a bad vacuum switch or ruptured CAD actuator diaphragm.
If one line has 20" +/- vacuum:
Move transfer case lever to 2WD, measure vacuum again. Lines should have swapped vacuum signals.
If No: vacuum switch bad or 4WD shift linkage needs adjusting
If Yes: Vacuum motor bad or stuck, or shift fork stuck: continue
Remove vacuum shift motor from the axle, attach vac lines to shift motor, engage/disengage 4WD. Does shift motor plunger move at least 1/2"?
No: shift motor bad
Yes: Check axle shift fork and vacuum motor for binding
Shift into 4WD and move truck a couple of feet
If light is still off, park truck, block the wheels, set the park brake, jack right front wheel, and try to hand spin the wheel
If wheel doesn't turn, 4x4 is functioning properly but there is a wiring problem: use an ohmmeter to check the 4x4 switch, wiring, fuse, and bulb.
If wheel turns freely, the front axle or transfer case is not engaged: continue...
Attempt to hand spin the front driveshaft If the driveshaft WILL spin, the transfer case is not engaged Check the transfer case shift linkage, problem is in linkage (or in the tran$fer ca$e internal$ <-- yes this means $$, ouch!)
If the driveshaft will NOT spin, the transfer case is engaged properly: continue...
USE CAUTION! With transmission 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 vacuum leak or bad vacuum switch.
If both lines have vacuum, look for a bad vacuum switch or ruptured CAD actuator diaphragm.
If one line has 20" +/- vacuum:
Move transfer case lever to 2WD, measure vacuum again. Lines should have swapped vacuum signals.
If No: vacuum switch bad or 4WD shift linkage needs adjusting
If Yes: Vacuum motor bad or stuck, or shift fork stuck: continue
Remove vacuum shift motor from the axle, attach vac lines to shift motor, engage/disengage 4WD. Does shift motor plunger move at least 1/2"?
No: shift motor bad
Yes: Check axle shift fork and vacuum motor for binding
Hall Of Fame
Joined: Jul 2006
Posts: 12,204
Likes: 10
From: Gainesville, Ga.
yes, more or less. its best to just put the whole truck up on 4 jack stands so you can run it in gear. you don't really need a vac meter. you can feel if its there or not.
the most common problems are pretty much everything about the vac system. the switch on the t-case. the lines going to the cad. rusty shaft in the cad. wire to the 4wd light, switch on the end . if that's ok, then you can get alignment problems inside the axle - bushings, burrs on collar or axle.
the most common problems are pretty much everything about the vac system. the switch on the t-case. the lines going to the cad. rusty shaft in the cad. wire to the 4wd light, switch on the end . if that's ok, then you can get alignment problems inside the axle - bushings, burrs on collar or axle.
Last edited by dhvaughan; Aug 8, 2010 at 08:20 PM.
Thread Starter
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Professional
Joined: Dec 2009
Posts: 203
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From: TN (423)
yes, more or less. its best to just put the whole truck up on 4 jack stands so you can run it in gear. you don't really need a vac meter. you can feel if its there or not.
the most common problems are pretty much everything about the vac system. the switch on the t-case. the lines going to the cad. rusty shaft in the cad. wire to the 4wd light, switch on the end . if that's ok, then you can get alignment problems inside the axle - bushings, burrs on collar or axle.
the most common problems are pretty much everything about the vac system. the switch on the t-case. the lines going to the cad. rusty shaft in the cad. wire to the 4wd light, switch on the end . if that's ok, then you can get alignment problems inside the axle - bushings, burrs on collar or axle.