4WD Issue...

Discussion in 'GM Powertrain' started by snowx7cac, Sep 7, 2007.

  1. snowx7cac

    snowx7cac New Member

    Hey, I'm new to this forum, so sorry if I do something stupid. Anyways, I'm having some 4wd issues. Couple months ago, I had the transmission rebuilt, and since then, my service 4wd light was on, and my dash switch wouldn't light up, or respond or anything, well, after replacing the encoder motor on the transfer case, the dash switch, the TCCM, and the actuator on the front axle, the service 4wd light is gone, and the buttons work. The only problem is now, when I first picked it back up from the dealer, i noticed it was in 4wd, so I pushed the button to put it in 2. Well, when i went to go, it didn't move, it acted like the transfer case was stuck in neutral, so I pushed the 4hi button again, and it made a loud bang, then acted like it had locked in, then i pushed the 2hi button again, and then it was fine. I tried using 4wd again tonight, and that same thing happened, but this time when i had the shifter in neutral and tried to change it to 4wd, i could hear the motor on the transfer case working, and i know the actuator on the front axle works, but it wouldn't engage into 4wd. Then i put it in park, and it made a sorta grinding noise, like something was rubbing against a gear in the transmission. I also tried 4 low, and even though it felt like it changed the gear ratio (more torque) the front tires were still not engaged. It also did the whole thing where it felt like it was in neutral, in fact, i put it in park one time, and it just kept rolling, so I dunno. I need some suggestions! I'm baffled now.

    Oh, btw, it's a 99 silverado z71 extended cab w/ the 5.3. Let me know your thoughts!
    Last edited by a moderator: Sep 7, 2007
  2. mhgoldwing

    mhgoldwing New Member

    Try this...

    When shifting to 4 hi and especially 4Lo, put the trans in neutral and let the vehicle roll slowly, less than 3-4 mph, and see if it shifts into and out of 4wd better that way. Moving helps the gears get synched.
  3. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    My understanding is you had a shop do this work. Before you break anything take the truck back to them and tell them to fix it correctly. If they give you any hassles get the regional or general manager involved. All these problems sound a lot like they're starting from the transmission removal and replacement.
  4. snowx7cac

    snowx7cac New Member

    K, i dunno if I mentioned this, but a few times when I did it, and went to put it in park, it made sort of like a grinding, or rubbing noise, like something wasn't meshing or something. Also, I haven't had the truck in the shop for this specific reason, just other 4wd related ones. The only thing done as far as major work goes was the transmission being rebuilt. Even then, they supposedly didn't do anything w/ the transfer case. Oh, I also tried all the switching to 4wd while moving and all that stuff. I called a shop today and they said it sounded like some internal problem, so we'll see. MIght just have to take a trip to the junkyard.
  5. kickercompkid_99

    kickercompkid_99 New Member

    Same problem

    Hey there, I have a 01 Silverado 2500HD and I had the same EXACT problem myself, except with mine it just all of a sudden happened while I was driving down the road, just out of the blue sounds like gears grinding, and I couldn't go anywhere!! Finally got it off the road by frantically switching between 4hi and 2hi and just keeping my foot to the floor. Got it towed home and shifted the transfer case into neutral, put the truck in park and got the old gear grinding again. So then I put it back in 2hi, and magically the truck would move! I know it's the transfer case so I got it all pulled but now I can't find anything anywhere about how to tear the damn thing apart so I can figure out what exactly broke in there, I can tell that the chain is fine so it must be something stupid with the internals. If anyone has any info on the nv623hd or just how to get the case apart it would be very much appreciated and very helpful, just wanted to let you know you're not alone!
  6. snowx7cac

    snowx7cac New Member

    Well, I guess it's sorta nice to know I'm not alone. I've pretty much come to the conclusion that it's the transfer case as well. I'm not going to tear it apart myself though. I think I'll just start looking in junkyards and online and what not to see if i can find one for a good price. Probably won't be til november or december though if I do. Can't really afford it right now...I hate house payments!
  7. kickercompkid_99

    kickercompkid_99 New Member

    Yeah, I know how that is, I feel naked without my truck! I did pull mine apart and couldn't find a thing wrong with it, so I just took it all apart and then put it all back together, that worked for about 5 minutes. But then tonight I thought I would just go out and cycle the transfer case through all the positions, did that and drove it around the yard and couldn't make the damn thing screw up, but I'm still afraid to drive it any distance at all for fear it will leave me stranded. I've been looking for a junkyard one as well, have still yet to find one for under $1000 and i'm sure if I took it to someone to rebuild it it would cost at least $500. Trying to find a cheap way out of this dilemma but it's not looking so good. If you find something that I don't know about let me know and I'll do the same for you!!

    Good Luck!!
  8. dannybaa1

    dannybaa1 New Member

    i,m having problems with my 99 Tahoe. i've replaced the actuator for the four wheel drive twice now. it's cost me 600.00 dollars each time and getting sick of it. now my fuse keeps blowing and the chevy dealer it's probably my actuator again.by the way my tahoe has 190,000 miles on it. I really want to keep it, everything else works great and i love the ride. is there a kit to make it a manual transfer
  9. unplugged

    unplugged Epic Member 5+ Years 1000 Posts

    Drivetrain.com lists one to fit, but check to make sure because others list it to fit up to the 1998 Tahoe. Check with NAPA, they might have the actuator. They had the one for my 1993 burb for less than $80 and I changed it myself in 15 minutes. I got the mfg part number from the dealer and NAPA cross referenced it.

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