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Whistle in 4x4

Discussion in 'Ford Trucks' started by tar, Jan 11, 2016.

  1. tar

    tar Junior Member
    Messages: 28

    I have an 03 f350 v-10 that developed a whistle above 25mph when I engage 4x4. Anyone heard of this? Front driveshaft was rebuilt last winter but the noise just started this winter.
     
  2. tjctransport

    tjctransport PlowSite.com Addict
    Messages: 1,390

    ESOF?? you may have a vacuum leak.
     
  3. tar

    tar Junior Member
    Messages: 28

    It is ESOF that works but I'm manually locked in.
     
  4. Too Stroked

    Too Stroked Senior Member
    Messages: 555

    Even when you're manually locking the hubs, if you have a vacuum leak, you will hear the sound of the leak trying to draw a vacuum.
     
  5. tar

    tar Junior Member
    Messages: 28

    Ok I'll look at the lines I have seals on the shelf might be time to use them
     
  6. tjctransport

    tjctransport PlowSite.com Addict
    Messages: 1,390

    does your heater work properly? a sign of a vacuum leak is all cab air goes to defrosters and no where else. no dash vents or floor heat.
     
  7. tar

    tar Junior Member
    Messages: 28

    I can switch the air, it sounds front driveshaft related some how. Hard to track down as it wasn't there today.