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3/4 ton Pump Rub

Discussion in 'Chevy Trucks' started by Squires, Oct 29, 2012.

  1. Squires

    Squires Senior Member
    Messages: 257

    Is this only on the electronic transfercase models or the manuel shift trucks as well?
    What can you look for without opening something up?
    Looking as a 2000 3/4 regcab longbox with 50,000km's
    Has dump insert,plow, and a new trans installed at the dealer in april of this year.
    Govt fleet vehicle, all dealer maintained.

    SHAWZER PlowSite.com Addict
    Messages: 1,288

    Okay, I will ask. What do you mean by pump rub?
  3. Plowtoy

    Plowtoy Senior Member
    Messages: 929

    Im not sure of what transfercases it affects, but I under stand that over time a hole will rub through in some transfercases where the oil pump gear is held in place. I would be looking for a fluid leak near the rear output housing. Other than that, without tearing it apart, I dont think there is anyway to tell.
  4. goel

    goel PlowSite.com Addict
    Messages: 1,079

    I had one go on a 2003. No warning, no idea it was gone until the truck got stuck one day. Put it in 4x4 and nothing.
    Apparently their is an upgrade available that I found out after it went.
  5. tuney443

    tuney443 PlowSite.com Addict
    Messages: 1,847

    There is no way to tell if your case is being gnawed on by the infamous pump rub unless you pull it apart or wait till the inevitable occurs.Lots of aftermarket fixes out there usually with some slick stainless steel hardware.
  6. goel

    goel PlowSite.com Addict
    Messages: 1,079

    Forgot to mention mine was the electronic dash push button. Went at about 180k. Also was not a cheap fix.
  7. nathan11507

    nathan11507 Member
    Messages: 68

    there is a way to tell when u see fluid rips left in ur drive or garage......cause i had the same on my 2002 avy 2500 cause there made outta magnesium....and u get holes oin them....i patcheds mine with jb weld and held up well even when i traded it in on another one that has less miles
  8. leigh

    leigh 2000 Club Member
    from CT
    Messages: 2,342

    2001 - 2006 GM transfer case(model 136, 146, 246, 261, 261HD, 263HD, 263XHD, 261XHD).
  9. Ajhenderson13

    Ajhenderson13 Junior Member
    Messages: 17

    I had one go bad on a 03 then had another transfer case problem on the reman not covered.....$1800.00x 2. Sold it and got an 06, fingers crossed.
  10. lilweeds

    lilweeds PlowSite.com Addict
    Messages: 1,178

    The fix is $75 from Merchant auto. Easy to do as well.
  11. Plowtoy

    Plowtoy Senior Member
    Messages: 929

    Yep, but he has had some problems with his repair parts a little while ago, so be careful.
  12. Squires

    Squires Senior Member
    Messages: 257

    Lost the auction so it is a non issue for now unless i find another similar truck.
    Thanks for the quick replies.
  13. tac48

    tac48 Member
    Messages: 41

  14. oakridgedriver

    oakridgedriver Junior Member
    from d
    Messages: 14

    I had my driveway paved and after a few months discovered fluid on it.....got under truck (04 sierra) and discovered seeping on transfer case. Wiped it all down and two weeks later, more dripping. Called a quick lube and asked where they thought it would/could leak from. They said from drain or fill plug, or from split housing gasket....well, wasn't leaking from those areas.....
    Joined gmtruck forum, typed in transfer case leak in the search field and low and behold several threads addressing the same issue.
    All gm trucks using the new process transfer case with dash switch, will eventually have the problem. On the forum, you can find a TSB that directs dealers to split the case and install a new spacer washer with an "L type tab" rather then the original useless flat washer, whenever a vehicle under warranty comes in with any transmission issues and inform customer that it was preventitive service. They are advised not to respond to any inquiries regarding "pump clip rub".

    In one of the threads, I found a picture that showed where it would be leaking from. I went outside, checked my truck and it had the exact same silver of a hole that you would never see or find unless you were aware of where it was. I checked prices, 1800 and up and thought all the repair does is prevent fluid from draining out.....for 1800???? (way out of warranty) So I did as was posted above, got out the jbweld and it's held for 2 years now.....$9. as opposed to $1800.

    Since then, the other journal recesses have worn through little tiny silvers as well. There are 4 slots where the flat spacer slides in to it's housing, and on 3 it can hit and wear through. The 4th slot has too much meat for it to get through and you won't have to worry about that one. The tough one to get to was on top of the transfer case, I did the same process, emery cloth, brake cleaner and jbweld. I used a mirror and a flashlight to do the job as the only other way is to take it all apart and drop it down. There are many pics on the forum that show how the pump spacer wears through and I posted some pics on my repair as well.

    In the U.S. there is a class action suit being forwarded on this issue. Apparently some wore through in a few thousand miles, and others later, some just after warranty expiration....and gm is apparently still using the same np transfer case.

    On another note....the encoder sensor becomes a little dirty inside, preventing a proper signal/postition.....my truck would "ghost" out of 2whlH for no reason.....discovered on the forum that the cause was grit or debris inside the sensor housing....so did as it recommended and tapped the housing very lightly with a hammer to dislodge the grit.....hopped back in truck and it works fine.....another inexpensive "fix".