Jump to content

Truck Not Locking Into 4wd Hi

jtkustomizer

By jtkustomizer
in Ask A GM Technician

Recommended Posts

jtkustomizer Enthusiast

jtkustomizer

Posted
Posted

I am new to this forum and I am having problems with the 4wheel drive in my 1998 GMC Sierra Z71.

The truck is not going into 4wheel drive like it is supposed too. When I put the key in and turn the truck on the lights on the switch all turn on and then go off after about 5-10 seconds. I can push the 4wd hi button and the both lo and high lights go on and blink continually and the truck doesnt lock into 4wd. If I push the lo button it switches into lo just fine and everything locks in like normal. but getting it back into 4Hi or 2wd takes a couple of button pushes.

 

I took it to a dealership and they told me the switch in the dash was bad and that the actuator in the front differential was bad as well. My dad has the exact same truck and everything works just fine on it, so I switched the switch and actuator out of his and into mine and it still does the same stuff and his is works just like it is supposed to. This issue has baffled me for a while now and since it has started snowing/ getting Icy 4wd would be really nice to have again.

 

 

Thanks in advance.

DofD Senior Enthusiast

DofD

Posted
Posted

Hi there and welcome to GM Trucks! :dunno:

 

The switch and actuator going bad are pretty common. But since you've eliminated those, hmm. Have you checked the wiring between the switch and actuator? Other than that, the better experienced here will need to chime in.

jtkustomizer Enthusiast

jtkustomizer

Posted
  • Author
Posted

I havent checked the wiring but when I had the actuator out I had my dad push the buttons and the actuator actuates while it is out just like it should. By the way does the actuator have to be lined up in a specific direction once it is installed or should it just be tightened like any othe nut/bolt.

 

 

I also tried 3 different in dash switches and they all do the same exact thing. I will take pictures/ and or video of what it is doing later tonight.

zaac Enthusiast

zaac

Posted
Posted

So you switched out the buttons and the front diff actuator; maybe you should switch out the TC encoder/actuator as well. I had to replace mine.

jtkustomizer Enthusiast

jtkustomizer

Posted
  • Author
Posted
So you switched out the buttons and the front diff actuator; maybe you should switch out the TC encoder/actuator as well. I had to replace mine.

 

 

Is this the one located on the transfer case. Does anybody have a picture of this?

zaac Enthusiast

zaac

Posted
Posted
So you switched out the buttons and the front diff actuator; maybe you should switch out the TC encoder/actuator as well. I had to replace mine.

 

 

Is this the one located on the transfer case. Does anybody have a picture of this?

 

Yes, it's on the front driver's side of the TC. You need to remove the front driveshaft, 2 electrical plug-ins and 3 bolts. 10 minute job. :D That's how it is on my 2000. I'm thinking '98 ain't much different.

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • mighty K20
      72 C10 headers question

      By mighty K20 · Posted

      FYI, I used sq body headers on my 72 and they were a perfect fit with zero clearance issues with the rods and Z bar for the clutch  I agree with post on worn mount rubber 
    • KARNUT
      Navigating senior years.

      By KARNUT · Posted

      I do most of my yard work before 10. My summer walks are usually at Kroger’s. Inside and yes I’ll do light shopping. Usually by noon you don’t want to be outside from June to September. The mail box is a good walk. I’ll walk there about 3 times before the mail comes. My house has two floors if I feel I need to move I’ll do the stairs. I’ll walk down the lane to our rent house with clippers trimming branches along the driveway. There’s always something to do. 
    • Grumpy Bear
      Navigating senior years.

      By Grumpy Bear · Posted

      There is a sign at my chiropractors office that says, "Don't quit, take a break." Sound advice.    On a 65 degree day (F) I can still work pretty darn hard (I'm 72). On a 85 degree day with a good deal of humidity it takes me three days to do what in took at 65 degree in three hours. If I work to muscle exhaustion (back) it will take me days more to recover. Taking breaks to prevent that is most useful. A lift belt has been very useful in preventing both.    Minister was giving a talk the other night where he was speaking of age and he used a clock to illustrate the human lifespan and it's ability to task. 1 to 45 was the second hand, scurry about. 46 to 70 the minute hand. Slower but...71 and up the hour hand...Hummm....until that talk I felt more like the minute hand. 😭   Then he says, the most useful hand on the clock is the hour hand. Without it you can't tell time. (Hour of the watch). I felt a bit better knowing we over 70 are useful. 🥹
    • mysery1
      Navigating senior years.

      By mysery1 · Posted

      I still do oil changes on our 2 vehicles and my motorcycle. I have a robot mower for the yard but can't use it in my backyard because my wonderful dog keeps digging the guide wire up so I have to push mow it. Not much of a walker especially during the summer, just to hot. I will ride my e-bike almost daily which helps to keep my knees and hips loose and helps with my balance. That's my story an I'll stick with it. We have been in the mid to high 90's with a feel like temp of 105 to 109 for the last month with no rain. We finally got some rain which cooled it off but were still stuck with the humdity. I do pace myself and that's why it takes me 2 days to do something that used to take a couple of hours.   Peace
    • DustMcGrath
      Transmission Temperature Hitting 220s

      By DustMcGrath · Posted

      @newdude great info, thank you!   So opening the thermal bypass valve early (or all the time) would cause temperature to rise more slowly, but above 194F there would be no difference from normal operation?   It seems like the only practical ways to bring down the peak temperature would be to improve the oil-air heat exchanger in some way or increase fluid capacity?

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...