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RPM and Overdrive for F550

Discussion in 'Trucks and Trailers' started by Markf, Mar 4, 2006.

  1. Markf

    Markf LawnSite Senior Member
    Messages: 406

    We picked up our "new" used F550 today from the dealer. On the way home I noticed that the OFF light for the overdrive on the shifter does not light up. I am now trying to figure out if the overdrive is on, off or is not working. At 70mph the truck is registering 2800 RPM. I assume that the truck has a 4.11 or 4.88 rear end. Any thoughts on this or how I can figure out the problem. Right now, taking it back to the dealer is a little bit of a hike. (50 miles one way). Thanks.
  2. Luvs2Play

    Luvs2Play LawnSite Member
    Messages: 246

    Did you push the OD button?
  3. Markf

    Markf LawnSite Senior Member
    Messages: 406

    Yes. That is how we know that the off light is not lit. My son has a 2000 F350 and it has the same set up.
  4. TLS

    TLS LawnSite Fanatic
    Messages: 7,943

    Maybe I don't understand, but why don't you press the button while driving at highway speeds and see if it goes (shifts) into and out of OD?
  5. Luvs2Play

    Luvs2Play LawnSite Member
    Messages: 246

    If the light is on, it is not in OD. The light should not come on unless the button is pushed. It should be off when the engine is started. I have not heard of one not coming on. I do know that it will flash if there is a problem with the transmission. It still should come on when you push the button. You may need to take it to a shop and have them read it, that should tell if there is a problem.
  6. Luvs2Play

    Luvs2Play LawnSite Member
    Messages: 246

    There was one time my light didn't work right, it was a shift solonoid problem. You could try unhooking the battery and hook it back up and try it, that won't remove any codes, but it will reset it.
  7. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Messages: 2,613

    Are you trying to suggest that this truck is locked out of od or something? Pushing the od button takes it out of od IIRC; maybe an F550 is different :confused:
  8. Gilla Gorilla

    Gilla Gorilla LawnSite Senior Member
    Messages: 923

    If the truck is used and the light was flashing for the previous owner and it was out of warranty for them they could have just pulled out the overdrive switch on the end of the shifter and pulled the plastic lense off then put a piece of black tape over it to keep it from flashing when they traded it into the dealership. This is probably a long shot though and hopefully it did not happen, or the light could be blown even though I have never seen that happen in 8 years working on Fords at a dealership.
  9. MMLawn

    MMLawn LawnSite Gold Member
    Messages: 3,569

    To anwser your question, I doubt seriously that if it is turning 2800 RPM at only 70 MPH that it is in OD. Shoot, my F350 only turns 1900 OUT of OD and in Tow/Haul mode pulling 7,000 lbs behind it. BUT, each time the power is turned off and then back on it should automatically "reset" and go into OD mode.
  10. Gravel Rat

    Gravel Rat LawnSite Fanatic
    Messages: 9,544

    A F-550 has pretty low gears expect the engine to run at anywhere from 2500-3000 rpm doing highways speeds. You will definatly know if the OD is off when you let off the throttle and the truck holds back.

    My F-450 with 5spd and 4:63s pulls at 100km/h (62mph) at 2500 or so.

    Its the fact of life when you have a 550 they are a heavy truck but you put a load in it she doesn't slow down. It prolly rides a little rough you will want to have a load in the box to tame the springs :laugh:

    Before you put the truck in service change all the fluids so change the engine oil, transmission and filter, rear diff. The automatic in the 550s is exactly the same as a F-250 so its a little out of its legue in a 19,000lb gvw truck.

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