2001-2007 Chevy/GMC Transfer case Severe and Sudden Failure Alert

Discussion in 'The Choo-Choo shop' started by 71GSX455-4SPD, Aug 18, 2010.

  1. 71GSX455-4SPD

    71GSX455-4SPD Nick Serwo Magic Car

    On my way back from Ohio my transfer case in my Avalanche decided to take a powder. Apparently, I was the victim of "pump rub" as explained below. As you read the links, you'll see that the pinhole in the transfer case caused by the pump shifting due to the failure of a cheap clip can be a real killer. As the small pinhole is above the normal fluid fill line, you won't have any driveway puddles as a telltale, but as your driving you're slowly pushing fluid out the pinhole and slowly causing your transfer case to fail.

    Now I changed my fluid last December and again it was check in May. It probably had less than 1,000 miles on since it was checked before heading to Ohio as it's not a daily driver.

    In my case, I started to hear a sound- not real loud- on my way home and as there didn't seem to be any driving issues and I was alone pulling my GSX in the middle of the night I kept going. This resulted in totally laying waste to the T-case to the point where I couldn't even get a core fee back it was that totalled.

    I get the impression from reading that most people who catch it early are able to get the case fixed (usually it's JB Weld or some other epoxy as the case is magnesium and hard to weld) and install an updated aftermarket piece on the pump that prevents future failure.

    I know there's a lot of guys out there with these transfer case models and it's probably worth checking out to see if you have a hole. If not, check the fluid with each oil change minimum or just bite the bullet and install the upgraded pump piece.

    As I said, you won't have any idea until it's too late and then hopefully it's an inexpensive fix. If you're like me and get caught in a situation where you don't want to stop in the middle of nowhere in the middle of the night with your expensive car, then it can get expensive fast.

    GM is obviously not interested in taking liability if this is true:

    Subject: TSB – Transfer Case Housing Failure #03-06-04-054 (04/01/2007)
    Models:2001-2007 Chevrolet Silverado
    2001-2007 GMC Sierra
    With Four Wheel Drive



    This bulletin is being issued regarding problems
    encountered with holes in the New Process Transfer cases used in
    all light duty pick up trucks.

    Several customers have been reporting holes developing in their transfer cases, particularly in high mileage vehicles.
    The source of this hole is from the internal transfer case pump rubbing against the housing and wearing through the case wall.

    ACTION:

    If the vehicle is within the specified warranty period service technicians should thoroughly clean the exterior
    surface of the transfer case around the hole. Apply a suitable amount of GM Adhesive, Part Number 142239JB (JB Weld) to ensure
    the transfer case leak will stop until the truck is out of warranty. Refill with the appropriate oil.

    If the vehicle is no longer within the warranty service period, deny any problem exists and blame the hole on:

    1) Improper maintenance
    2) Collision Damage
    3) Off road incident
    4) Road debris


    Under no circumstance should you acknowledge the condition referred to as “Pump Rub”.
    If questioned, deny that it exists, except possibly in vehicles meant for overseas sales.


    GM Bulletin #03-06-04-054
    For Internal Use Only

    EDIT: Above found on Internet and appears to not be a real GM bulletin, so disregard!


    *******************************

    Part of a PI found:

    Subject: Improved Oil Fluid Wear Pump Clip - keywords 136 149 246 246EAU 261 263 263EAU housing leak case transfer transfercase #PIP4118 - (04/17/2007)

    Models: 1998-2007 Light Duty Trucks and Utilities
    Equipped with New Venture Gear Transfer Cases RPO NP1, NP2, NP3, NP4, NP8
    --------------------------------------------------------------------------------
    The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

    Condition/Concern:
    Oil pump wear clip P/N 12470559 is broken or out of position. This may cause the pump to wear a pin hole in the transfer case rear half. If the wear is severe the transfer case may be damaged due to lack of lubrication. The clip may fatigue and break. The clip may become loose and shift out of position.

    Recommendation/Instructions:
    A new clip design has been released. P/N 89059653 is available for both production and service. This new part totally cancels and supersedes the former P/N 12470559. Only the new clip will be available.

    This new oil pump wear clip should be used whenever a transfer case is opened for any type of internal service. See photo. GMSPO currently has inventory of the new part.

    Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

    *************************


    Check out the links below:

    http://www.dieselplace.com/forum/showthread.php?t=293199

    http://www.dieselplace.com/forum/showthread.php?t=185097&highlight=pump+rub+tsb

    http://www.kennedydiesel.com/categoryresults3.cfm?Category=11&SubCategory=109&SubCategory2=135

    http://www.merchant-automotive.com/tech/tcp.pdf

    It seems totally hit or miss, so I'm posting this in hopes of helping someone out before it's gone too far.
     
    Last edited: Aug 19, 2010
  2. kenm455

    kenm455 Gold Level Contributor

    hi Ken.as a 25 yr GM tech i'm going to say i have never seen a bulliten like the one you listed first that tells you to do a cheap patch/coverup to get it past warrenty.when i enter the bulliten listed (03-06-04-054) it comes up as
    an updated injector balance test with tech2 for 01-03 duramax engines.
    i don't dispute the fact that the transfer cases do wear through at the pump housing.i can usually replace a dozen t/cases a in a winter season for that condition.the biggest failure i come across is the clutch apply plate bearing melting.but this is usually caused by customers driving on the highway at 120-130 kph in 4wd or auto mode.
    thanks,Ken
     
  3. GSXMEN

    GSXMEN Got Jesus?

    A friend of mine's mother's truck had the t-case go bad last year. Hers was a '99 half ton. After talking to the guys at the yard about a replacement, they said the 99 & newer ones had some real issues. Sounds like it's a very common problem.
     
  4. GoldBoattail455

    GoldBoattail455 462 -> TH400 -> Posi

    Ken,
    Sorry to hear of your troubles. As an authorized GM Warranty Fleet I can say that is not a GM Bulletin. It sounds more like the words of an angry customer. I'll look up the bulletin when I get to work. I have not seen this in any of the trucks at work.
     
  5. Topless64-455

    Topless64-455 Well-Known Member

    A fellow board member was at my house and we had to put fluid in his transfer case because he was getting tranny fluid all over the bottom of his truck. That was 5 years ago and I think they replaced his case for him. It was a Duramax pickup.
     
  6. 71GSX455-4SPD

    71GSX455-4SPD Nick Serwo Magic Car

    On that bulletin I did note "if this is true". You can't believe everything you read on the Internet, so discount it especially as it comes up as injector related. You're probably right, just some angry customer that made it up and it got picked up on several forums.

    On the other hand, the T-case failures are very real and if you're out of warranty can really run some $$ depending on the level of damage. I have no idea if the failure rate is is 1 in 100 or 1 in 10,000, but as it happened to me and I found a fair amount of info and pics on various boards I thought I'd post it.

    That machined aftermarket fix looks like it would be a good preventive measure, especially if your case is starting to eat itself from the inside out, as it isn't just a weak clip and provides much more engagement.

    From 1/2 ton trucks to the HD Duramax trucks over a large span of years with this problem, there's a lot of guys here that rely on those vehicles to pull some really nice cars, whether race or show. And as it can be a fairly sudden failure (check fluid end of May all was fine, towed to Ohio in July/early August and toast), I thought it might be of help. I have 91kmi on my 2500 Avalanche and I really don't have much that is bad to say about it, so I'm not bashing GM trucks at all.

    Forewarned is forearmed.
     
  7. Steve Reynolds

    Steve Reynolds SRE Inc

    Does anyone know if this problem exists with one ton (K3500) trucks? I'm assuming that they use a different transfer case than the 1/2 and 3/4 ton trucks? I have a 2003 one ton dually, 4x4 with the 8.1 and Allison trans, 65,000 miles.

    Should I worry?

    Steve
     
  8. 71GSX455-4SPD

    71GSX455-4SPD Nick Serwo Magic Car

    From the above, I believe these are the transfer case numbers affected:

    136 149 246 246EAU 261 263 263EAU

    Take a look at the plate on yours and see if any match. That should give you a good indication. I believe the common theme is the magnesium case, if what I read is correct.
     
  9. bostongsx

    bostongsx Platinum Level Contributor

    Its the same running gear on the 3500, I just replaced one of these last week in my 02 2500 hd.
     
  10. SmittyDawg

    SmittyDawg Need another garage....

    Hey Ken...thanks for the heads-up on this.:TU:

    I just went out to the garage and looked at my truck
    2002 Tahoe with 235K+ miles on it
    246-NP8 transfer case

    Transfer case is clean as whistle and no hole in the problem area. :)

    My question to the group is, should I do some preventative maintenance and open up the case, replace with the new clip or whatever needs to be done?
    Is there still a good chance that this problem may occur if left alone, especially considering the mieage?

    Thank you for your thoughts on the matter!

    Cole
     
  11. kick71

    kick71 Mike

    Thanks for the heads up on this Ken. My daily driver is an 07' Z71 Suburban that is still under warranty. I will check the code.

    Mike
     
  12. 71GSX455-4SPD

    71GSX455-4SPD Nick Serwo Magic Car

    No problem, Mike, just sort of a public service announcement. I just got home from picking mine up and boy am I glad to have the truck back! One year unlimited mileage warranty on the reman case. I'm going to put in my outlook calendar a reminder to make sure I check thoroughly in 11 1/2 months! If it still looks good, I may think of updating it with that machined aluminum piece anyway for good measure.

    Cole, I guess it's a crap shoot. With that kind of mileage maybe you're safe as it hasn't happened? :Do No:
     
  13. SmittyDawg

    SmittyDawg Need another garage....

    Thanks, Ken. As I read through a bunch of threads over at dieselplace.com forum, I think I have been lucky up to this point. Lots of highway miles has been a good thing in this case. I am going to get the fix kit from Merchants and install it before the holes begin!:TU:
     
  14. nick rabi

    nick rabi Well-Known Member

    The transfer case on my 06' Chevy 2500hd took a crap on the way home from the BPG nats.Took it to the trans shop,not a drop of fluid in the case & no obvious signs of leakage.Makes sense to me now.:gp:
     
  15. 71GSX455-4SPD

    71GSX455-4SPD Nick Serwo Magic Car

    Dude, this year? Maybe we shouldn't travel together! :cool: j/k

    If they did a rebuild on your case, then the hole may very well still be there again spewing fluid. As it's magnesium, seems like JB Weld is the repair of choice for the tiny pin hole.
     
  16. nick rabi

    nick rabi Well-Known Member

    Yeah Dude,This year!!!!Got a remanufactured unit also.Mine started screaming as soon as we got into PA.Then my trailer lights blew out.Should have known it was going to be a fun ride home when the trailer ramp pin let go & the ramp fell down while doing 70mph in WV on rt 70:Dou:
     
  17. 71GSX455-4SPD

    71GSX455-4SPD Nick Serwo Magic Car

    Well, at least I was behind you to see the sparks on that one and pull the rest of the posse over. Is that ramp 6 inches shorter now? :Brow:

    Yardley knew I was having noise from the drivetrain before I split off onto 81, but I guess you and I never talked about it. We both had the same problem at the same time. And so you had the same decision to make that I did- keep going or stop in some obscure place with your nice car in tow. I thought it was my front diff as it had puked some extra fluid from what was apparently a slight overfill all the way onto the driver outside frame rail- the direction of the vent. I figured as the front diff just goes for the ride in 2wd and a seal must have blown I'd keep going. I was surprised to hear it was the transfer case. The noise never got obnoxiously loud. With the radio on even at a fairly low volume and with highway wind and engine noise you couldn't even hear it. However, when all was said and done the guts of mine were so torn up I couldn't turn it in as a core. You'd have think that with that kind of damage the whole truck would be shuddering or moaning or possibly even the case just grenading and leave me stranded.
     
  18. 5ofus

    5ofus New Member

    Hello All,

    I own a 2004 Z71 Suburban that started making a noise last weekend which sounds like someone is shooting a three round burst out of an M60. The noise is intermittent, so the first mechanic was unable to reproduce it the two times we took it to him. He suspected the Transfer Case and sent me to a transmission shop. I went for a test ride with the second mechanic and we did hear the noise three times, the first two times it was an individual bang or knock, then the burst. We did not hear it again so he put it on the lift this afternoon, but could not see anything. To me, while driving, it sounds like it is coming from under the drivers seat or just behind, but today I was in the passenger seat and it sounded like it was coming from the rear drivers side. Anyone have any ideas?
     

Share This Page