GM Truck Club
THE PREMIER CHEVY TRUCK & SUV FORUM
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER
Results 1 to 10 of 10

Thread: TCase Question

  1. #1

    Default TCase Question

    My 99 Sierra has push button 4wd but not the "auto" button so would my Tcase be auto or manual? The truck manual makes it sound like it is auto but everything that I have read online has made it seem that it is manual. Please help I need to know if I should put ATF or Autotrac II in it. Thanks


    03 Chevy Silverado 1500 ext cab Z-71
    79 AMC Spirit GT
    77 Olds cutlass supreme

  2. #2
    Master Mechanic clgoch187's Avatar
    Join Date
    Aug 2010
    Location
    Gettysburg, Pennsylvania, United States
    Posts
    900

    Default

    I might be wrong here but id say use the atf....that what most use toll you get to the newer ones with the blue transfer case fluid. And there isntuch difference between the manual levered and push buttons, it just an electric motor that turns the shaft instead of a lever. If nothin else check your owners manual
    03 Silverado 1500
    285/75/16 BFG's
    2 Blaupunkt 10" vW1000 subs in Subthump box
    ProComp Level Lift & 3" rear blocks

  3. #3
    Legend

    Join Date
    Sep 2010
    Location
    everett, massachusetts
    Posts
    1,324

    Default

    manual is when you have a lever ..since you have push buttons this is automatic.

    auto 4X4 is an added feature to the 4X4 selection with the automatic 4wd.

    now gm was using Dexron III in these transfercases. what GM did was replace this with the new improved trac II fluid.

    I would call a dealership and with your vin they will tell you what to use and if they have the fluid in stock. you will need a little over 2 qts. only torque the plugs to 15 ft lbs..too tight you will crack the case. case is soft metal. open the fill plug first.drain with the vehicle warmed up from operation..

    the transfercase works all the time ...so even it you do not use 4X4 very much it requires regular fluid replacing.

  4. #4

    Default

    nI would look at your rpo code in the glove box. the tcase code start with an N like NP8.

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors, http://www.gmtruckclub.com/forum/sho...5-GMC-Yukon-XL
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  5. #5

    Default

    Quote Originally Posted by j cat View Post
    manual is when you have a lever ..since you have push buttons this is automatic.

    auto 4X4 is an added feature to the 4X4 selection with the automatic 4wd.

    now gm was using Dexron III in these transfercases. what GM did was replace this with the new improved trac II fluid.

    I would call a dealership and with your vin they will tell you what to use and if they have the fluid in stock. you will need a little over 2 qts. only torque the plugs to 15 ft lbs..too tight you will crack the case. case is soft metal. open the fill plug first.drain with the vehicle warmed up from operation..

    the transfercase works all the time ...so even it you do not use 4X4 very much it requires regular fluid replacing.
    Yes, Calling the dealership sounds like a good idea. Thanks

    - - - Updated - - -

    Quote Originally Posted by Pikey View Post
    nI would look at your rpo code in the glove box. the tcase code start with an N like NP8.
    I have two RPO codes that start with NP.... NP5 and NP8

  6. #6

    Default

    Quote Originally Posted by Z-71 View Post
    I have two RPO codes that start with NP.... NP5 and NP8
    Try this site: http://www.rpocodes.com/

    NP5 is the steering wheel

    NP8 is the t-case (it's called an active t-case)
    Ray

    '09 Avalanche LTZ - Black
    '05 Envoy XL (sold)

  7. #7

    Default

    if you have RPO code "NP8" you have the NVG246 transfer case.
    The transfer case requires Auto TracŪ II Fluid GM P/N 12378508

  8. #8

    Default

    Quote Originally Posted by Pikey View Post
    if you have RPO code "NP8" you have the NVG246 transfer case.
    The transfer case requires Auto TracŪ II Fluid GM P/N 12378508
    Thank you.... Someone put Trans fluid in it, Do you think any damage was done?

    - - - Updated - - -

    - - - Updated - - -

    Quote Originally Posted by RayVoy View Post
    Try this site: http://www.rpocodes.com/

    NP5 is the steering wheel

    NP8 is the t-case (it's called an active t-case)
    Thanks I will check that site out
    Last edited by Z-71; 11-24-2013 at 12:27 PM. Reason: messed up

  9. #9
    Legend

    Join Date
    Sep 2010
    Location
    everett, massachusetts
    Posts
    1,324

    Default

    no but trac II is a better fluid. as I stated before GM used this dexron III back when your vehicle was OEM built. could be the OEM 1999 fluid still in it !

  10. #10

    Default

    Quote Originally Posted by j cat View Post
    no but trac II is a better fluid. as I stated before GM used this dexron III back when your vehicle was OEM built. could be the OEM 1999 fluid still in it !
    Thanks, I guess I will be buying some fluid and do a fluid change then.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •