Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

front driveline won't disengage

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by creampuff90k5, Jan 23, 2003.

  1. creampuff90k5

    creampuff90k5 1/2 ton status

    Joined:
    Feb 15, 2002
    Posts:
    142
    Likes Received:
    0
    Location:
    New Jersey
    front driveline won\'t disengage

    A week or so ago, I posted about a bad vibration at speed. Turns out that the front driveline won't disengage and has been turning the whole time. The thing is, I don't know where to start: At the hubs or at the transfer case?

    Could it be that the T-case is turning the driveshaft and axle, but not the wheels because the hubs are unlocked? Or is it more likely that the hubs are stuck and turning everything up until the T-case?

    In either situation, what should I do? This is bad timing 'cause I just installed the ORD weld-in frame repair and am REAL SICK of working on the truck out in the freezing cold! Oh yeah, the hubs are the original electric units and the transfer case is an NP241 rebuilt about two years ago.

    Thanks in advance for your help.
     
  2. heavy4x4

    heavy4x4 1/2 ton status

    Joined:
    Aug 28, 2002
    Posts:
    3,270
    Likes Received:
    0
    Location:
    Delafield, Wisconsin
    Re: front driveline won\'t disengage

    Well it could be either, but I'm guessing hubs. If you're driving down the road with the hubs locked (not disengaged) than the front driveshaft will spin. Likewise, if you're hubs are unlocked - yet your t-case is in 4H, the front driveshaft will spin. (Technically this cannot happen with auto hubs because if your t-case is engaged in 4H, then your hubs will be too)
    First of all, make sure the t-case is in 2H. Then, have someone look at your front driveshaft as you drive a bit. If it's spinning, put the vehicle in reverse and drive backward a good 15 feet - trying to get the hubs to disengage. If that doesn't do it (ie, the front shaft still spins when driving forward), go buy some manual hubs and swap out the autos. That's what I did.

    BTW, how's the ORD brace? Did it install easily? Tighten up any steering feel? Thanks...looking to buy one for my '90 as well. (nevermind...I thought it was the bolt-in one, that's the one I'm looking at getting, not the weld in. Did your frame crack, or is this just preventative maintenence?)
     
  3. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    Re: front driveline won\'t disengage

    </font><blockquote><font class="small">In reply to:</font><hr />
    the hubs are the original electric units

    [/ QUOTE ] The hubs aren't electric, they're just automatic. They sense when the axle shaft is trying to drive the wheels and then lock automagically. They're supposed to unlock if you back up in 2WD for about 10 feet. But it sounds like yours have failed. /forums/images/graemlins/frown.gif Pick up a set of locking hubs, install them and you should be all set. /forums/images/graemlins/cool.gif
     
  4. creampuff90k5

    creampuff90k5 1/2 ton status

    Joined:
    Feb 15, 2002
    Posts:
    142
    Likes Received:
    0
    Location:
    New Jersey
    Re: front driveline won\'t disengage

    Well, I already tried the 4H to 2H then backing up process several times and it still won't release. It sounds like a consensus that the hubs are the most likely culprit, then? Are they tough to replace?

    Heavy4x4, I had major cracks around the steering box, so the frame repair kit was a necessity. Since I have zero welding skills and no welder, I simply removed the steering box and anything else that was in the way like the rubber inner fender flaps) and called a freelance welder with a mobile setup to come by and do the job. Took 20 minutes tops, then I put everything back together.

    Have to say that it did not really help the sloppy steering, though. Still 6-8" of play in the steering wheel and the box is pretty new and properly adjusted as well. Yet another project! Good grief...
     
  5. JayHornyak

    JayHornyak Registered Member

    Joined:
    Feb 15, 2001
    Posts:
    18
    Likes Received:
    0
    Location:
    Clinton Connecticut
    Re: front driveline won\'t disengage

    Lift up the front end and spin the drive shaft with the truck in park. If your drive shaft won't spin then the T case is locked up if the front wheels spin then it is the hubs. /forums/images/graemlins/k5.gif
     
  6. creampuff90k5

    creampuff90k5 1/2 ton status

    Joined:
    Feb 15, 2002
    Posts:
    142
    Likes Received:
    0
    Location:
    New Jersey
    Re: front driveline won\'t disengage

    GREAT IDEA! Thanks.
     
  7. HarryH3

    HarryH3 1 ton status Author

    Joined:
    May 31, 2000
    Posts:
    10,384
    Likes Received:
    2
    Location:
    Georgetown, TX
    Re: front driveline won\'t disengage

    If the transfer case was staying engaged in 4WD he would know it at the first corner he came to on dry pavement. That builds up so much driveline windup that it feels like someone has stepped on the brake pedal. /forums/images/graemlins/shocked.gif
     
  8. heavy4x4

    heavy4x4 1/2 ton status

    Joined:
    Aug 28, 2002
    Posts:
    3,270
    Likes Received:
    0
    Location:
    Delafield, Wisconsin
    Re: front driveline won\'t disengage

    </font><blockquote><font class="small">In reply to:</font><hr />
    Still 6-8" of play in the steering wheel

    [/ QUOTE ]

    Wow, that is a lot. If your box is o.k then there are only three things that could be the culprit/should be replaced. Tie rod, drag link, and steering shaft - but I'm sure you already know all that.
    Good luck with the steering and the hubs. They're cake to install - search through the "garage" for any install questions, there have been some rather recent posts about the issue.
     
  9. imiceman44

    imiceman44 1 ton status

    Joined:
    Aug 5, 2002
    Posts:
    15,160
    Likes Received:
    1
    Location:
    Sacramento, CA
    Re: front driveline won\'t disengage

    Actually there is a fourth:
    the frame will still be weak if it was cracked and now has the patch on, he will need to put the bolt on brace as well to tighten it up.
    The only situation the bolt on brace doesn't help is if you have crossover steering then you will need another type of brace.
     

Share This Page