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Gear indicators not working? Not shifting right?

Discussion in 'GM Allison' started by Sparky8370, May 4, 2008.

  1. Sparky8370

    Sparky8370 Do chickens have large talons

    1,703
    0
    May 3, 2008
    New Hampshire
    I'm putting this here because I haven't seen an allison forum yet. If one gets created the mods can just delete this part and move it if they'd like.


    Last year I had the nsbu switch on the side of the tranny let go. The old version is black and susceptible to damage. There is an updated part that is tan that is supposed to be better. I haven't had any problems with mine since I replaced it. The part number is 29540479 and you're better off getting it at an Allison dealer.
    Mine was a two plug deal, allison went to a single plug later, and then put them inside the tranny. So if you have a newer one the part number may not be the same. Just look and see how many plugs you have.

    With mine the resin inside the switch had heated up pretty good and pretty much bonded the switch and plugs together. I just broke the old switch apart carefully so I didn't damage the plugs, and scraped all the resin off the contacts in the plugs with a dental pick. I then used elec contact cleaner, di-elec greased them, and sprayed silicone electrical connection waterproofing on the outsides.

    Hope this can help someone out. Feel free to add to this if you have more info.
     
  2. schulte

    schulte ACCELLERANT!!!

    420
    0
    May 4, 2008
    Southern CT
    Weird, I've never heard of it getting hot enough to melt. Did your tranny usually run hot?
     
  3. Sparky8370

    Sparky8370 Do chickens have large talons

    1,703
    0
    May 3, 2008
    New Hampshire
    no, higher current flow than it was designed for. As the connection got worse from corrosion and resin the current draw was even more. Or at least that's what I'm assuming. Tranny runs cool like most of them do.
     
  4. emerson

    emerson Ugly is cheap

    92
    0
    May 9, 2008
    Prince George BC
    For those who need one; get it from the Allison dealer. Mine cost $82 vs. $255 from GM.
     
  5. Philbilly2

    Philbilly2 Just a speck on the wall

    I can add a little, snow can take them out, water packed inside of them on mine and others will take them out.
     
  6. 4wdaaron

    4wdaaron Hard Worker

    So should I clean up the old one or buy a new one?
     
  7. schulte

    schulte ACCELLERANT!!!

    420
    0
    May 4, 2008
    Southern CT
    Puddle jumping is what killed mine...
     
  8. Diesel Dually

    Diesel Dually awaiting your return...signed... your friends

    506
    0
    May 3, 2008
    Mile High
    Buy one to get going, fix the old one for a spare.
     
  9. 4wdaaron

    4wdaaron Hard Worker

    good idea!
     
  10. SFC Cobb

    SFC Cobb Jesus Freak

    1,910
    0
    May 15, 2008
    Hurst, TX
    The plugs on mine had to be heated to get them disconnected. There is a sealant on the connectors. They plugged back in OK. This is from the mech that replaced it and I believe him since I know him.
     
  11. Mike L.

    Mike L. Recruit

    128
    0
    May 5, 2008
    A heat gun should allways be used to remove the connectors. Make life a lot easier.
     
  12. 4wdaaron

    4wdaaron Hard Worker

    so what would cause a truck to have these symptoms, but not be the NSBU??? my dad's '02 still isn't right, even though we put in a new NSBU last night! It still blinks in reverse sometimes and shifts hard from reverse to drive and vice versa.
     
  13. Sparky8370

    Sparky8370 Do chickens have large talons

    1,703
    0
    May 3, 2008
    New Hampshire
    Bad wiring?? Do you have any codes?
     
  14. 4wdaaron

    4wdaaron Hard Worker

    There is a new code.. I didn't here a number from dad, but he said its something to do with the torque converter possibly. Hopefully I can find out that code, but until then I appreciate any possible ideas, because its not looking good from here on out.
     
  15. Philbilly2

    Philbilly2 Just a speck on the wall

    let me know the codes and we can try to get you going
     
  16. modified

    modified modified

    27
    0
    May 16, 2008
    NE Wisconsin
    Moisture and electronics don't mix!
    If the NSBU wasn't too old, I'd remove the electrical plugs, inspect pins/plug for damage, dry it out with a heat gun, coat with dielectric grease, and try it again.
    I always carry a spare.
     
  17. SFC Cobb

    SFC Cobb Jesus Freak

    1,910
    0
    May 15, 2008
    Hurst, TX
    That sounds like the NSBU but the shifting hard could be filters. Has the trans been serviced regularly by changing the external filter and flushing the trans which also flushes the internal filter?

    If not then a complete trans service including the internal filter should be done. It also is the symptom of a sticking valve body.
     
  18. 4wdaaron

    4wdaaron Hard Worker

    Yes it has been serviced, we didn't flush the trans, but fluid has been changed and new filter put on. It's going into our cousins shop so he can hook it up to a computer and control the valve bodys / look for bad wiring.
     
  19. Mike L.

    Mike L. Recruit

    128
    0
    May 5, 2008
  20. Mike L.

    Mike L. Recruit

    128
    0
    May 5, 2008
    Factory glue crap, not heat and I see it all the time.
     

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