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Standard Transmission ID

Discussion in 'GM Powertrain' started by jtiffany78, May 30, 2010.

  1. jtiffany78

    jtiffany78 New Member

    Ok, I've tried searching the threads and internet trying to figure out what transmission could be in my1988, K1500 Silverado, standard cab, long bed.
    I was told by the previous owner that a heavy duty diesel transmission was put in it so the numbers in the glove box don't do me any good since the truck has always been powered by a gas motor.
    I got underneath the truck and pulled these numbers:
    15694903GAKH
    1500 C 02 1795
    Castrol syntoro LT
    GM P/N 12346190
    Chrysler P/N 4637570

    The last three lines pertain to the transmission fluid and I've searched using the numbers/letters in the first line but nothing gets it. The closest I've found is 15691903GAKH...The 1 is the difference. I double checked the tag on the transmission to make sure I didn't misread it, and it's correct. And the site I found says it's on a 2wd, mine is a 4wd. It looks similar to the NV4500, with only minor differences in the main body of the transmission. I'm not sure if those are the differences in the heavy duty versus the medium duty. 1st gear is a granny gear, and the rest are normal.

    The reason I'm trying to figure it out is because the synchronization gear going into 3rd is bad and I want to replace it. Basically like shifting without the clutch, I have to find the sweet spot before it will go in.


    Any thoughts, websites or knowledge to share??:neutral:


    Thank you in advance!
  2. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    I know that the gas motor did come with a low gear in 1988, with the diesel as well. I have a 2500 with the gas motor and no low gear 4spd with OD (5spd).. Why not have it rebuilt? Then you know what you have (or is this what you are planning??).. I would say your best bet is to take those numbers to a GM dealer, and have them translate them for you. I have had to have that done a few times now since there is such a mix of parts in 1988...
  3. jtiffany78

    jtiffany78 New Member

    I am planning to rebuild it actually, but I was hoping to do it myself and learn something about transmissions. Good idea about going to a GM dealer though, not sure why I couldn't think of that.

    I will give that a try when the holiday is over, thanks!!:great:
  4. murdog94

    murdog94 Epic Member 5+ Years 5000 Posts

    And If nothing else get part numbers from them etc, and you can order aftermarket parts with a part number cross reference.. You do have a great tranny their though.. There have been a few times that i wanted a granny gear pulling my boat out of the water.

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