Ford Windstar Tranny won't stay in Overdrive

Discussion in 'Other Auto Tech' started by rconaway, Sep 20, 2009.

  1. rconaway

    Founding Member

    Joined:
    Nov 11, 1999
    Messages:
    1,410
    Likes Received:
    3
    Trophy Points:
    39
    Location:
    Phoenix, Az.
    Gentlemen and Ladies,

    I'm tearing my hair out on this one and could really use some help. My 2000 Ford Windstar with 165K miles and just passed emissions with flying colors (I run synthentic oil), won't stay in Overdrive. I get on the freeway 3 miles from my house. For the first 10-20 miles, the van runs fine. As the freeway mileage continues, anything above 75 mph makes the van drop down out of overdrive. As the mileage continues, so the does the speed that the van needs to maintain to stay in overdrive. Anything over 74, then 74, and so on down to 60mph and then eventually it just won't stay in Overdrive at all. If I'm driving an hour, it won't go back into overdrive at all, even under 40mph with no throttle.

    The trigger to this is if I'm driving 75mph and I click the cruise control to go up 1mph, it should just slowly go faster. As the problem kicks in, it just downshifts and then may or may not go to overdrive. As I continue driving, it just won't go down.

    I cleaned the MAF and the air filter. I did a complete tranny fluid change and also checked for codes. No luck. I'll take any other ideas before I pull the tranny.
     
    #1
  2. KBExperience

    KBExperience Active Member

    Joined:
    Jun 21, 2009
    Messages:
    1,178
    Likes Received:
    18
    Trophy Points:
    49
    Location:
    Houston
    is there an overdrive switch? i'd check that
     
    #2
  3. rconaway

    Founding Member

    Joined:
    Nov 11, 1999
    Messages:
    1,410
    Likes Received:
    3
    Trophy Points:
    39
    Location:
    Phoenix, Az.
    There is a switch on the tranny stalk on the console. It works normally when the tranny is working correctly. After the tranny starts staying in Overdrive, it won't do anything other than make the light go on and off.
     
    #3
  4. MrToolBelt2

    MrToolBelt2 New Member

    Joined:
    Aug 11, 2010
    Messages:
    3
    Likes Received:
    0
    Trophy Points:
    0
    Identical Problem

    I have exactly the same problem on 1999 Ford Windstar, 3.8L. There is no sense describing anything more as you have described the problem perfectly. I'm afraid it is a worn overdrive servo but am holding out hope that it might be a bad solenoid valve or sensor. Did you ever identify or solve the specific problem or did you resort to a complete rebuild?

    Thanks!
     
    #4
  5. rconaway

    Founding Member

    Joined:
    Nov 11, 1999
    Messages:
    1,410
    Likes Received:
    3
    Trophy Points:
    39
    Location:
    Phoenix, Az.
    I haven't had time to address it but it's getting slightly worse. On longer drives now, the o/d light comes on and starts blinking. I'm going to take it to ford and have them do a diagnostic but I also fear that a new tranny is in order. We gave the van to the 16-year old and he just drives within a couple miles of the house so it's not a critical issue but I will find out this what my Ford dealer says. Worse case, I buy a used tranny and swap it out.
     
    #5
  6. MrToolBelt2

    MrToolBelt2 New Member

    Joined:
    Aug 11, 2010
    Messages:
    3
    Likes Received:
    0
    Trophy Points:
    0
    Thanks for the reply!

    You know that old joke about telling the doctor that it hurts when i do this...
    The doctor says, "well, don't do that!"

    We have got a bit more information about the trigger condition for the problem on our van. It seems that if the accelerator is to the floor and you are getting on the highway, if the shift to 4th (overdrive) is delayed past 75 or so, the problem begins and gets progressively worse exactly as you described. Otherwise, you can drive the car for hours with no problems. Actually, the fact that the problem has caused the OD light to come on in your case is VERY encouraging to me. This can mean that the PCM is detecting a fault condition that may be mechanical, but more likely it is getting input from sensors that is not expected. This has occurred on our van in the past and I replaced one of the external sensors like the speed sensor or the fluid temperature sensor. I forget which one. Both are in the troubleshooting list for this problem in the service manual as well.

    I will be bringing our van to the local Ford dealer to get the codes read from the PCM with the NGS tester and to run the on board diagnostics. I'm always leery to do this as I've been told several times by the dealer mechanics that based on the codes they read I needed a new transmission. A new pump shaft, sensor and a solenoid valve later the transmission has more than 180k miles on it and it has never been removed from the car (the pump shaft is behind the valve body which can be serviced in the car). I will politely nod my head and leave and research the problem at home once I know the codes.

    If there are no control problem codes, I will worry more about mechanical problems like a worn servo. If there are codes, I will hunt for a faulty sensor using the service manual electrical test procedures.

    Please let me know what you find out at your dealer.

    thanks!
     
    #6
  7. rconaway

    Founding Member

    Joined:
    Nov 11, 1999
    Messages:
    1,410
    Likes Received:
    3
    Trophy Points:
    39
    Location:
    Phoenix, Az.
    Mine is very simlliar but will eventually go to 3rd after a few miles even if I don't exceed 75. Mine is around 70 after about 3-4 miles and then drops to 60 or so. I have a reader so I'll check it out in a few minutes.
     
    #7
  8. MrToolBelt2

    MrToolBelt2 New Member

    Joined:
    Aug 11, 2010
    Messages:
    3
    Likes Received:
    0
    Trophy Points:
    0
    Is it an NGS (New Generation Star) tester?
     
    #8
  9. rconaway

    Founding Member

    Joined:
    Nov 11, 1999
    Messages:
    1,410
    Likes Received:
    3
    Trophy Points:
    39
    Location:
    Phoenix, Az.
    No, it's one of the SCT's for my Mustang. However, the kids took the van so I won't be able to do it until later tonight. I did try the foot to the floor thing and sure enough, it went into 4th gear.
     
    #9
  10. sasngang

    sasngang New Member

    Joined:
    Oct 29, 2010
    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    0
    I have the same problem. Here's my thoughts. The trans starts slipping out of overdrive after the fluid warms up. I can get about 15 minutes of overdrive when the vehicle is cold (after overnight). (my thinking is...) As soon as the trans warms up, then starts to not hold in OD (OverDrive) and will eventually not hold at all in OD. If continued to drive without disengaging the OD system, the constant slippage is causing the ATF to heat up beyond normal operating range and ultimately the trans warning light starts to flash on the dash. If you dis-engage the OD (using the button at the end of the shift lever), then you can drive it indefinately with no problems (other than really poor gas mileage, like 15mpg at 65mph or worse when going faster as the motor is running 3300rpm or more. I don't know the internal workings of this trans... but my thinking is the servo (if it is like a piston), is leaking enough fluid when the trans warms up to not hold and it just gets worse when the temp increases. I have added a viscosity adder to the trans fluid and it helped, but not enough for it to hold when getting hot. I would welcome any thoughts about my evaluation. AND does anyone know if the servo might be accessible without completely removing the trans? I think it's located under a side cover (right???).. Please help.
     
    #10

Share This Page