1979 GMC Suburban 2500 4X4

Discussion in 'GM Powertrain' started by Sara_Mae, Apr 13, 2009.

  1. Sara_Mae

    Sara_Mae New Member

    First off....hello all.

    I used to own a 1990 GMC Suburban 2500 4X4. (lost him to a freeway accident)

    Now I own a 1979 GMC Suburban 2500 4X4. I am having a hard time getting the truck into four wheel drive.

    When I go to engage four wheel drive I:

    -place the veihicle in "N"
    -then proceed to shift down into "4 high"

    There is a teeth grinding sound.

    I found that if I put the transmission in neautral and then turn the truck off, shift into 4X4, then turn the truck back on, it is then engaged. Is this the right way to engage four wheel drive in this model year?

    ~Sara Mae :glasses:
  2. bry2500

    bry2500 New Member

    welcome to the site!!!!

    Not sure on the problem. I'll do some research for ya though.
  3. MWright936

    MWright936 New Member

    Welcome to the site!!
  4. vncj96

    vncj96 New Member

    Welcome to the site! Not sure about your truck, but the last time myself or parents had a manual shift transfer case it was put tranny into neutral while rolling 5-10mph and toss it into 4hi and go. This was on a 90 and 92 suburban and a 85 1/2 ton
  5. Z71_guy

    Z71_guy New Member

    welcome to the site
  6. Jimmiee

    Jimmiee New Member

    Welcome aboard. Leave your transmission in Drive and shift directly from 2 Hi to 4 Hi and back without going to neutral. It will shift easier if you are moving forward. You can go from 2WD to 4WD at any speed below 50 MPH. If you select neutral then it will grind. This is normal. Once you select neutral and your transmission is in Drive then everything inside the transfer case is spinning.
  7. 04sierracrewcab

    04sierracrewcab New Member

    Welcome to the GMTC.
  8. Sara_Mae

    Sara_Mae New Member

    Shifting into 4hi while in motion makes more sense than sitting there in neautral. I called mechanics but they either didn't know or they said something is wrong with the transfer case.....I am skeptical about that though.

    Thanks for the HI's

    Sara Mae
  9. bigburb

    bigburb New Member

    In my old burb I have to be going like 5 to 7 mph tops to get it to shift smoothly into 4hi. And of course, I have to be stopped and in nuetral to get into 4low.

    Let's see some pics of that new burb of yours too!
  10. Sara_Mae

    Sara_Mae New Member

    Actually Bigburb, my Suburban looks like your little avtar suburban, same color and everything. I am getting some photos together. There are a lot of things I want to do to my new burb. Figure I would get something that is a bit older, in order to work on it easier, well, for me.

    Sara Mae
  11. omnisi

    omnisi New Member

    I noticed in your sig tha tyou have a "V 1500" 1990 Suburban...? I have a 90/4x4/6.2 and when I was looking for a lift, there was always a V1500 and an R1500 in the vehicle model choices. What is the difference between a V1500 and an R1500 ??

    Thanks

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