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Truck Tranny Problems

Discussion in 'Truck & Equipment Repair' started by PinkyRingz, Dec 8, 2008.

  1. PinkyRingz

    PinkyRingz Member
    Messages: 39

    2002 GMC Sierra 3500/Duramax Diesel/Allison Automatic Transmission/ 210,000 kilometres.

    Truck will slip out of gear. Put in drive and move ahead maybe fifty feet then the truck goes into the neutral and the gear indicator light blinks. Shift to any other gear and does the same.
    Let the truck run for a bit then it will shift hard and awful then go...seems to start in second gear then shifts up.
    Tranny fluid is a little low. No metal bits on the dipstick and doesnt smell burnt.

    Ideas?
     
  2. danknight60

    danknight60 Member
    Messages: 46

    sounds like the start of a big problem i would bring it in to have it service before you brake some big it sounds like a gear is worn out so it might be an easy fix OK

    good luck bro
     
  3. PinkyRingz

    PinkyRingz Member
    Messages: 39

    ........that sux.....and RIGHT after i get the plow on and working too....figures...lol
     
  4. snow7899

    snow7899 Senior Member
    Messages: 238

    I would bring it to a shop (or dealer) and have the codes read on the tranny computer. The flashing light is telling you there is a fault in the system. Sounds like the tranny is going into limp home mode.
     
  5. SullivanSeptic

    SullivanSeptic PlowSite Veteran
    Messages: 3,422

    Question about new allison

    Hey guys, I have a 2007 2500hd NBS with the LMM Duramax. Does anyone know the proper maintinace schedule for the Allison. I am getting conflicting reports from my dealer and a couple of the guys in the shop.

    I own a couple of diesels but never one with an Allison tranny
     
  6. Spitz

    Spitz Senior Member
    Messages: 192

    Gm has had trouble with the older range switches and such, some even have you install a shield to keep snow and water away from it.. Definatly nothing can be for certain on the internet, best take it into a shop who can see it..


    Service- I usually flush any transmission at 50k or less no matter what the fluid looks like, then again i do my own so its not a big deal to me.. No idea what the recommended changes are though. ATF breaks down just like any fluid though, keep that in mind. The allision isnt much different from any other trans though, just larger with a little more software power behind it.
     
  7. snow7899

    snow7899 Senior Member
    Messages: 238

    On your 07 2500 duramax, the book suggests every 25K under the severe service. I recommend at least once a year, don't forget the transfer case, I do it at the same time.
     
  8. no lead

    no lead PlowSite.com Addict
    Messages: 1,308

    see why they need a bailout? GM=lost money
     
  9. NICHOLS LANDSCA

    NICHOLS LANDSCA PlowSite Veteran
    Messages: 4,302

    FYI 06' and newer Allisons require dextron VI
     
  10. Livingreen

    Livingreen Junior Member
    from Indiana
    Messages: 24

    did you figure out why it was slipping out of gear?
     
  11. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    I flush them 50k or dirty whatever comes first, no matter who says what.
     
  12. Rangerman

    Rangerman Senior Member
    Messages: 148

    Oh brother the guys are right about the range switch weve had that twice in one truck take it to ur dealer they will fix it. As far as the last comment about flushing if u want to buy a need tranny flush. That is the worst thing u could do that stirs up all the metal and gets rid of the sludge. Trannies are like humans theres good and bad colesteral theres good sludge and bad sluge thats why theres a break in period for new trucks.
     
  13. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    Thats about the stupidest thing I have heard in a long time. How the hell does it stir anything up? It ads no aditional pressure then what the trans puts out. And the fluid flows in the same direction. Ive done hundreds with 0 problems. How many have u done? Please explain how It stirs up contimants in the transmission.
     
  14. Rangerman

    Rangerman Senior Member
    Messages: 148

    I have had countless people tell me that mechanics, people who work for allison trans, and what good does it do if its not adding some pressure how do you expect ur filter to get clean if its going the same direction would that be fluid through the filter to the moving parts. Wow seems to me like that would take the new fluid throught the dirty filter and into the trans. Sounds to me like its all adds up to about 3000-5000 down the drain when you can change the fluid so easily.
     
  15. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    Most newer transmissions do not have Filters they have screens and if the fluid never gets very dirty not much of a need to change the internal filter. It is a good idea to change them though periodicly.The flush machine's purpose is not to clean the filter its purpose is to excange 99% of the old fluid for new nothing else.Please exlpain how u change 99% of the old fluid with new please?
     
    Last edited: Dec 11, 2008
  16. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    Well there like u and dont know what there talking about.Next time the tell u something that dont make sence ask them to explain.Change the filter before u flush it if u where so worried about it.U did not explain how it stirs up debris.
     
    Last edited: Dec 11, 2008
  17. Spitz

    Spitz Senior Member
    Messages: 192

    Well a lot of the sediment seems to stick to the pan and obviously the magnet. That and the fluid is a detergent fluid so it suspends as much junk as it can untill it goes through the filter. The allison 1000 does have a serviceable filter in the sump, even though i dont think allison recommends it be serviced. Gm transmissions i've seen that arent taken care of (filter+ flush) usually dont last beyond 100k, alot we do service regularily end up lasting a lot longer. You want to remove the pan, clean it out and replace the filter. This removes a lot of the used oil, makes it easier for the machine to remove (dilute) the rest. But like said it does remove a lot of the used oil, and you need to replace that oil as it does break down (obviously). Look at it, it does get dark and starts to stink. That fluid is 3x as important as motor oil is to a motor. Its the coolant, lubrication and the source of any power the transmission makes.. Its definatly a good idea to keep nice, new fluid in an auto.
     
  18. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    Spitz have u ever had one come back with shifting problems after u have done a flush? I have Been using the same style machine since 2003 with 0 problems.
     
  19. Spitz

    Spitz Senior Member
    Messages: 192

    Not any that were legitimate. When i say legitimate i mean not even the same part of the vehicle complaints.. You did a trans flush and now my ujoints squeek.. Stupid stuff like that.
     
  20. brad96z28

    brad96z28 PlowSite.com Addict
    Messages: 1,526

    Ha ha Ya I hear you there. I dident think U have had any problems either . Thanks.:salute: