GMC Truck Forum banner

1 - 16 of 16 Posts

·
BIG boys want BIG toys
Joined
·
129 Posts
Discussion Starter #1
I have a 99 GMC Z71 (new body style), I am having trouble with the 4 hi & 4 low on my push buttons, you can hear the transfer case working when you push the buttons but the frount tires will not pull. The 4 auto workes just fine. I have already changed the swich in the dash. any other suggestions...
:insane:
 

·
BIG boys want BIG toys
Joined
·
129 Posts
Discussion Starter #4
front drive shift spins even in 2 hi , what is the axle actuator or the servo??????
 

·
Registered
Joined
·
1,816 Posts
I think the servo he's talking about is the one in the transfer case that shifts it into whatever gear. I'm talking about the actuator on the front driveshaft that engages the front axle. Its about the size of a coke can on the passenger side top side of the axle. They shouldn't be too hard to change, but it would be a good idea to make sure thats the problem first. I forgot that the autotrac cases have the front shaft spinning all the time...
 

·
BIG boys want BIG toys
Joined
·
129 Posts
Discussion Starter #8
I ve checked the actuator it semes to work fine. what about this servo in the front axle, where is it and how can i check it?????
 

·
Registered
Joined
·
1,816 Posts
99Z71 said:
I ve checked the actuator it semes to work fine. what about this servo in the front axle, where is it and how can i check it?????
:think: You checked the actuator? Then you should know where it is...since its on the front axle...
 

·
Registered
Joined
·
1,816 Posts
Whifflebat said:
I think the servo he's talking about is the one in the transfer case that shifts it into whatever gear. I'm talking about the actuator on the front driveshaft that engages the front axle. Its about the size of a coke can on the passenger side top side of the axle. They shouldn't be too hard to change, but it would be a good idea to make sure thats the problem first.

99Z71 said:
I ve checked the actuator it semes to work fine. what about this servo in the front axle, where is it and how can i check it?????
:read: :read:

I have no idea what you checked. Did you check the SERVO that shifts the transfer case, or did you check the ACTUATOR that engages the front axle?

I have never heard of a servo going out on the tcase, although it woudln't surprise me. I have heard of the front axle actuator going out, often. Now which did you check?

To check the front axle actuator, pull the actuator out of the axle housing, and shift the truck into 4x4 with the key in the run position without the engine running. It should move back and forth when you switch it from off to on and vice versa. If you can stop it with your hand, it may be too weak to
engage the axle.

no need to call anybody an asshole.
 

·
[>
Joined
·
3,255 Posts
Whifflebat said:
.....
no need to call anybody an asshole.
:word: Play nice


Sounds like the Actuator IMO. Do as Whifflebat said to check it. Sounds like the T-case is working.
 

·
BIG boys want BIG toys
Joined
·
129 Posts
Discussion Starter #13
sorry about the "asshole" thing just a little frustrated about the 4 wd.

I did check what you call the Actuator, it is on the front axle, it's black a little smaller than a coke can. I unscrewed it from the axle, and with the truck running i made a bubby switch it from 4 hi to 4 lo to 2 hi to 4 auto. It did move in and out in all gears, I did notice that in 4 hi and 4 auto it stayed in the same postion i asume it should becuase they are the same gear, the only difference, auto only lets the front tire pull when the back tire start to slip. In 4 hi they should pull all the time. Am I correct in saying this? ( my front tire do pull in 4 auto but not in any other gear.) I will check the actuator again, this time putting pressure on it with my hand like u said.

Is there anything else that engages the front tires besides the axle, i ve heard of some older model truck that have magnets that lock the hubs in. Are maybe i am just totaly confused. please help......... :bawl:
 

·
Registered
Joined
·
1,816 Posts
Well, if the front axle actuator is working correctly, and you say the front wheels do pull in auto, it sounds like you may have something wrong with the transfer case. Not sure what though, I've never heard of a problem like this, mines manual :D Couldn't hurt to check all the connections under there. Hopefully someone else more familiar with that case will chime in....
 

·
BIG boys want BIG toys
Joined
·
129 Posts
Discussion Starter #15
:bawl: well went to the gm dealer friday they checked the transfer case. They told me the cluches in the transfer case were sliping.
any one know were i can get a rebuild kit and a book on how to tear it apart. :nono:
 

·
Registered
Joined
·
2 Posts
99Z71 said:
:bawl: well went to the gm dealer friday they checked the transfer case. They told me the cluches in the transfer case were sliping.
any one know were i can get a rebuild kit and a book on how to tear it apart. :nono:
Any updats to your problem 99z71??
 
1 - 16 of 16 Posts
Top