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  1. #1

    Default NP203 is Full-time 4WD. Why locking hubs?

    I am new to Chev trucks and and have two questions-

    1. I just picked up a 1979 K20 with an NP203 transfer case and manual locking front hubs. I am a bit confused with the configuration. The NP203 is Full-time 4WD. Why locking hubs?

    2. Unfortunately, both hubs are in poor shape. Should I replace them?


  2. #2


    Someone added locking hubs to defeat full time 4wd, probably trying to improve gas mileage.
    This was a common mod to do on these trucks in the early 80's when fuel prices started climbing.

  3. #3


    Thanks much for the reply and clarification. Is there any advantage to going back to the original configuration or should I just buy a set of new hubs and install them?

  4. #4


    Welcome to the club, it's good to have you aboard.

    2002 Chevrolet Silverado Extended Cab SportSide: See Mods in My Garage

  5. #5


    This was a common mod to do on these trucks in the early 80's when fuel prices started climbing.
    When my dad did this mod on his '75, the kit not only included locking hubs, but it also included parts to convert the full-time case to a part time case. Perhaps before you worry about going back to the original configuration, do some checking to see if your 203 case is still in the original condition or if it has been converted.
    '98 K1500 Suburban LS 5.7 L 4L60E NV246 ARB
    '92 Ford Explorer XLT 4x4 4.0 L A4LD BW13-54 Trac-loc rear
    "My toys were the greasy cogs and springs and pistons that lay around all over the place, and these, I can promise you, were far more fun to play with than most of the plastic rubbish children are given nowadays." Danny in Roald Dahl's Danny The Champion of the World

  6. #6


    The advantage would be to save a little fuel, opinions on the strength of locking hubs and fulltime systems range back and forth, I personally think their about even, in the past I've broken both systems under roughly the same conditions.
    Do you know what mfg made them? I haven't looked in a while but Warn (one of the most popular for this conversion) and Mile Marker both offered rebuild kits that were slightly cheaper than a new hub kit. Finding the parts to go back full time might be a little harder to do also.
    Unless the outer hub is broken you should be able to save some money by rebuilding what you have.

  7. #7


    Welcome to the G M TC ! Lookls like your getting some good info', good luck!

    2010 Z/71 Colorado C/C
    Black 4X4 w/5.3L V8
    2007 Winnebago Adventurer
    w/8.1L Chevy & Allison 6spd.
    Canyon Lake, Texas

  8. #8



  9. #9

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