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2500hd 8.1/allison weird noise

Discussion in 'Chevy Trucks' started by chris694205, Oct 17, 2010.

  1. chris694205

    chris694205 Senior Member
    Messages: 175

    when i start my truck when its cold it has some kind of a whining noise.. Seems to be coming from the back of the engine somewhere... when you rev the truck the noise gets louder as the rpms gain... any ideas? it goes away after the truck gets warm after a minute or so
     
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    What year? Check the fluid level recently? Change the external filter lately?
     
  3. chris694205

    chris694205 Senior Member
    Messages: 175

    its an 03. since this post i saw the one about the internal filter sucking air and its scaring me a little. i have just changed both filters and fluid along with the transmission lines. it only does it on and off for the first 30 seconds or so after starting when it sat all night or a couple days
     
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Definitely want to recheck your work then, paying special attention to the internal filter. Because that's where the issue very likely lies.
     
  5. chris694205

    chris694205 Senior Member
    Messages: 175

    i hear ya... i was very careful installing it but maybe the seal around the tube got somehow messed up. could you think of anything else if that isnt the problem?
     
  6. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Not until you're sure the filters ok. :D Hope you used a genuine Allison internal filter too...
     
  7. chris694205

    chris694205 Senior Member
    Messages: 175

    Sure did that's why I'm hesitant to think that's the problem. We'll see tomorrow
     
  8. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Just because it's a genuine doesn't mean it's fully installed or the install wasn't compromised in some way so re-check it. I ask because the generic filter quality isn't the greatest overall and I've seen a few crack around the pickup tube too.
     
  9. nhgranite

    nhgranite Senior Member
    from N.H
    Messages: 122

    where do you get a gen ally filter? gm dealer or chain store?
     
  10. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

  11. mkwl

    mkwl 2000 Club Member
    Messages: 2,361

    Should the internal filter be changed at a certain interval, or just the external and replace the fluid from dropping the drainplug?
     
  12. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    The internal is intended to last for the life of the trans Matt but I never leave them in that long. While the pan is down for a fluid change (about every 25K or so depending on the fluid used and conditions the trucks used under) the filters right there anyway so I do them then. And change the external filters about every 15,000 mi or so, or once a year whichever comes first.
     
  13. 496 BB

    496 BB Senior Member
    Messages: 789

    I think its normal. Mine whines like a supercharger every time when its colder out. Does it also when warmer out but not as loud. Never had a problem with it. Its just the Allison.

    Surprised you dont hear the piston slap of the motor. Sounds like every rocker arm is loose for 5 minutes :D
     
  14. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Yes they do have a little sing to them that's normal but if it's a new or much more pronounced sound (as I'm understanding it) then no it's not normal.



    Wouldn't be surprised if yours cries out in agony every time you hit the key. :D
     
  15. 496 BB

    496 BB Senior Member
    Messages: 789

    Mine loves me! It shifts so smooth you cant even feel it unless you get on it hard then it shifts hard enough to break loose going into 2nd.