4WD Won't Engage
04-06-2007, 10:30 PM
#22
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Join Date: Apr 2007
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4X4 won't engage
My 4 wheel drive would not engage, here are the initial conditions
and my solution.
I turned the switch to 4H, heard the relay, and the 4x4 lamp came on.
The front axle was not engaged.
So, I had an assistant pull forward as I looked at the front drive shaft.
BE CAREFUL NOT TO RUN OVER YOUR BUDDY!
Since it DID turn, I looked at the vacum switch on the front axle by
removing the cover. While the ESOF switch was operated between 4H
and 2H, I noticed that the actuator was moving very slowly in the 4H
position. It never had enough strength to engage the front axle.
Then I swapped the vacum lines and the problem was reversed:
(Wouldn't disengage)
I followed the "bad" vacum line up to the two little solenoids on the passenger side firewall, and blamed one of them.
I decided to replace both because they were the same age.
If you find yourself in the same position, write down the engineering #'s
from the parts and call the parts dept. These things are not too expensive.
Hope this helps someone,
L24
and my solution.
I turned the switch to 4H, heard the relay, and the 4x4 lamp came on.
The front axle was not engaged.
So, I had an assistant pull forward as I looked at the front drive shaft.
BE CAREFUL NOT TO RUN OVER YOUR BUDDY!
Since it DID turn, I looked at the vacum switch on the front axle by
removing the cover. While the ESOF switch was operated between 4H
and 2H, I noticed that the actuator was moving very slowly in the 4H
position. It never had enough strength to engage the front axle.
Then I swapped the vacum lines and the problem was reversed:
(Wouldn't disengage)
I followed the "bad" vacum line up to the two little solenoids on the passenger side firewall, and blamed one of them.
I decided to replace both because they were the same age.
If you find yourself in the same position, write down the engineering #'s
from the parts and call the parts dept. These things are not too expensive.
Hope this helps someone,
L24
04-07-2007, 03:24 PM
#25
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Warranty
I haven't read all the posts in this thread but.. I have a 2005 and it only has 11k miles on it. At about 10k I had the same problem. I have a warranty so I took it into the dealer and they just said that the 4wd switch went out. It was totally covered and they said that they had a few with the same problem within the last couple months. So.. that is more than likely your problem.
07-29-2012, 06:54 AM
#27
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I saw those two solenoids the other day when out there looking at my specific problem where my 97 electronic 4x4 seems to be locked in low lock. My switch seems to have zero effect and I don't hear the relay kick in when moving it. No 4x4 light on dash, but seems to be stuck in low lock. I am headed out there now to look for these vacuum lines to the front axle, but did not expect that.
Otherwise, I will be trying to hit the bell housing / and or pulling the electric motor to see if I can just get it out of low lock. Can't really afford to replace parts, but also can't afford to drive around in low lock. :-(
Hopefully a simple fix, but I registered to thank for this information and hope it does help others.
Updated: I swapped the vacuum lines (more like air shock lines at the solenoids with no change. Ended up pulling the electric motor and moving the manual shaft over to 2h and test drove. I now can drive my truck above 40 miles per hour. I don't like being without 4x4 but I did not use it as much as I liked. One day I will replace the motor if that is it. I was not able to manually move the motor back to 2h or I would have mounted it back up.
Thanks for this forum as I am at least able to have transportation again!!! - Everyone rocks for the shared knowledge!!!
Otherwise, I will be trying to hit the bell housing / and or pulling the electric motor to see if I can just get it out of low lock. Can't really afford to replace parts, but also can't afford to drive around in low lock. :-(
Hopefully a simple fix, but I registered to thank for this information and hope it does help others.
Updated: I swapped the vacuum lines (more like air shock lines at the solenoids with no change. Ended up pulling the electric motor and moving the manual shaft over to 2h and test drove. I now can drive my truck above 40 miles per hour. I don't like being without 4x4 but I did not use it as much as I liked. One day I will replace the motor if that is it. I was not able to manually move the motor back to 2h or I would have mounted it back up.
Thanks for this forum as I am at least able to have transportation again!!! - Everyone rocks for the shared knowledge!!!
My 4 wheel drive would not engage, here are the initial conditions
and my solution.
I turned the switch to 4H, heard the relay, and the 4x4 lamp came on.
The front axle was not engaged.
So, I had an assistant pull forward as I looked at the front drive shaft.
BE CAREFUL NOT TO RUN OVER YOUR BUDDY!
Since it DID turn, I looked at the vacum switch on the front axle by
removing the cover. While the ESOF switch was operated between 4H
and 2H, I noticed that the actuator was moving very slowly in the 4H
position. It never had enough strength to engage the front axle.
Then I swapped the vacum lines and the problem was reversed:
(Wouldn't disengage)
I followed the "bad" vacum line up to the two little solenoids on the passenger side firewall, and blamed one of them.
I decided to replace both because they were the same age.
If you find yourself in the same position, write down the engineering #'s
from the parts and call the parts dept. These things are not too expensive.
Hope this helps someone,
L24
and my solution.
I turned the switch to 4H, heard the relay, and the 4x4 lamp came on.
The front axle was not engaged.
So, I had an assistant pull forward as I looked at the front drive shaft.
BE CAREFUL NOT TO RUN OVER YOUR BUDDY!
Since it DID turn, I looked at the vacum switch on the front axle by
removing the cover. While the ESOF switch was operated between 4H
and 2H, I noticed that the actuator was moving very slowly in the 4H
position. It never had enough strength to engage the front axle.
Then I swapped the vacum lines and the problem was reversed:
(Wouldn't disengage)
I followed the "bad" vacum line up to the two little solenoids on the passenger side firewall, and blamed one of them.
I decided to replace both because they were the same age.
If you find yourself in the same position, write down the engineering #'s
from the parts and call the parts dept. These things are not too expensive.
Hope this helps someone,
L24
Last edited by RSexton; 07-29-2012 at 08:12 AM.