Overdrive Question

nalley4 Dec 14, 2019

  1. nalley4

    nalley4 Test Drive

    Messages:
    19
    Ok I just bought a second Xterra, a 2005 S 4.0 2wd. My question is when driving I have to keep the OD off or she will keep downshifting and upshifting. Plus tach reads higher than when I turn OD off. I’m getting better gas mileage with it off. Is this normal in the second gens or what? Previous owner stated it had been checked out by multiple transmission mechanics and can find nothing wrong/or a reason for it doing this.
     

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    Last edited: Dec 14, 2019
  2. Brunnie

    Brunnie Bought an X Supporting Member

    Messages:
    143
    Location:
    Colorado Springs
    First of all, when OD is turned off you are in 4th gear so naturally the engine will run faster (tach will read higher) than if it is 5th gear (OD).
    Secondly, if your transmission is hunting between 4th and 5th, you're right at the point where the computer senses that you are in the wrong gear, lugging the engine so it downshifts. In that respect it is normal. Maybe the question that needs asking is... at what speed is this shifting occurring?
     
  3. nalley4

    nalley4 Test Drive

    Messages:
    19
    I am running lower RPMs with OD off.
    With OD on it doesn’t seem to matter what speed I’m running. 55-60, if my speed slows down any, it will downshift with OD on. When speed moves up, it up shifts. It’s a constant thing because no one can hold a single speed. With OD off tach hangs anywhere from 22-2500 rpms. If I turn OD on, she jumps to 3000-3200. Hope this helps any confusion
     
  4. Brunnie

    Brunnie Bought an X Supporting Member

    Messages:
    143
    Location:
    Colorado Springs
    When you say OD "on"... is the light on the dash illuminated?

    In 5th gear, OD on (dash light not illuminated), 22-2500 at 60-65 mph is the sweetspot, and normal rpm range.
    At that speed, turning OD off (dash light illuminated) the rpms should jump up to about 3000 rpms.
     
    Last edited: Dec 15, 2019
  5. Brunnie

    Brunnie Bought an X Supporting Member

    Messages:
    143
    Location:
    Colorado Springs
    From the Owner's Manual:
    Overdrive switch
    Each time your vehicle is started, the transmission is automatically “reset” to overdrive ON.
    ON: With the engine running and the shift selector in the D (Drive) position, the transmission upshifts into Overdrive as vehicle speed increases.

    Overdrive does not engage until the engine has reached operating temperature.


    OFF: For driving up and down long slopes where engine braking is necessary push the Overdrive switch once. The O/D OFF indicator light in the instrument panel comes on at this time.

    When cruising at a low speed or climbing a gentle slope, you may feel uncomfortable shift shocks as the transmission shifts into and out of Overdrive repeatedly. In this case, depress the Overdrive switch to turn the Overdrive off. The O/D OFF indicator light in the instrument panel comes on at this time.

    When driving conditions change, depress the Overdrive switch to turn the Overdrive on.

    Remember not to drive at high speeds for extended periods of time with the Overdrive off.
    This reduces fuel economy.
     
  6. nalley4

    nalley4 Test Drive

    Messages:
    19
    When my light is illuminated is says OD off.
    I know this all sounds weird but does as stated in other post. With my OD off/light illuminated, I have lower rpms than when OD is on/light NOT illuminated. Even at operating temp, any reduction in speed she will downshift. Any increase in speed she will up shift(with OD on/light not illuminated. With OD off/light is illuminated and gear indicator is in 4, I get lower rpms and better gas mileage
     
  7. nalley4

    nalley4 Test Drive

    Messages:
    19
    I will try to post a video tomorrow to clear any confusion as to what I am describing. It acts as though it is reversed. Weird as everything I said sounds, that is exactly what it is doing. Multiple mechanics( so I’m told) were unable to find anything amiss or have any idea as to why it does this. Even a road test and no answers.
     
  8. Brunnie

    Brunnie Bought an X Supporting Member

    Messages:
    143
    Location:
    Colorado Springs
    IMHO... something is reversed and I seriously doubt that "multiple mechanics" looked at it. If that (multiple mechanics) is true I'd be at the dealership and letting them look at it. Something is definitely amiss.
     
  9. TerryD

    TerryD Total Tease Supporting Member

    Messages:
    1,377
    Location:
    Covington, Va
    Could be slipping in 5th not allowing the TCC to lock up. But that should set a DTC IIRC.

    Checked you fluid level? Hot, engine running, cycle through the gears, put in park and check.
     
  10. nalley4

    nalley4 Test Drive

    Messages:
    19
    It was at the Nissan dealership and they couldn’t find anything or explain it. By multiple, there were 3. I have all service records since the previous owner bought it. And he owned it a number of years and stated it has done that ever since he bought it. I have warmed it, cycled the gears, checked fluid, she just had filter and fluid changed. It doesn’t seem to be hurting anything. So ass backwards we’ll be.
     
  11. nalley4

    nalley4 Test Drive

    Messages:
    19
    My check engine light is on. I’ve only had this X less than a week. I haven’t had the opportunity to run a scan on it. But do know it has a O2 fault because there were 2 new cats put on and didn’t replace the 02 sensors at that time(again I have the service records. I’ll get her scanned and see if any codes show.
     
    TerryD likes this.
  12. TerryD

    TerryD Total Tease Supporting Member

    Messages:
    1,377
    Location:
    Covington, Va
    Lead with the check engine light next time please. MOST faults in the 2nd Gen will show up there and should be taken seriously.
     
  13. nalley4

    nalley4 Test Drive

    Messages:
    19
    I didn’t lead with the check engine light because there is no code for anything with the issue. I tried posting a video but will not let me upload. Going to try some Lucas transmission anti slip and see if that helps.
     

    Attached Files:

    TerryD likes this.
  14. nalley4

    nalley4 Test Drive

    Messages:
    19
    Ok I got a bit of an update. I erased the codes and cleared the check engine light. Driving with OD on she was not downshifting and up shifting but the rpms were at the 3500 range. I don’t know what the heater control bank 1 sensor 2 fault even means but the other is O2 sensor. I guess time will tell about the shifting. Still want to add the Lucas and see if that helps.
     
  15. maillet282

    maillet282 If you bleeding, Imma fix you Moderator Supporting Member

    Messages:
    6,421
    Location:
    Ontario Canada
    Are you bypassed? If not What color is your trans fluid and what color is your radiator fluid ?
     
  16. nalley4

    nalley4 Test Drive

    Messages:
    19
    nalley4Test Drive
    New
    Bypassed? I don’t know.
    Previous owner had transmission serviced at the dealership. As well as reversing the radiator and transmission lines. This was done less than 1 yr ago. It’s reddish. Not the strawberry color thank goodness. Radiator fluid is good. He stated that this issue has been going on since he bought the Xterra some years back.
     
    Last edited: Dec 15, 2019
  17. TerryD

    TerryD Total Tease Supporting Member

    Messages:
    1,377
    Location:
    Covington, Va
  18. nalley4

    nalley4 Test Drive

    Messages:
    19
    I haven’t checked the tail lights, but I will today. Thanks for the info on the sensors. I got new ones but haven’t had time to change them yet.
     
  19. nalley4

    nalley4 Test Drive

    Messages:
    19
    The codes for mine were P0037 and P0430. P0430 is my 02 sensor, the other is heater control something
     
  20. TerryD

    TerryD Total Tease Supporting Member

    Messages:
    1,377
    Location:
    Covington, Va
    The tail lights being on after key-off is an indicator you're having issues with the IPDM which is involved in many of your systems. Not a fool proof thing, because it's sometimes hard for a computer to tell if it's lost its mind.
     
    nalley4 likes this.
  21. nalley4

    nalley4 Test Drive

    Messages:
    19
    Nothing wrong with the tail lights. But on the way into work this morning, the check engine light returned. And so did the up shifting and downshifting. Codes are the same as before. Need to replace ASAP but can’t believe that would cause the reversed OD/shifting issues
     
  22. Zack.

    Zack. Bought an X Supporting Member

    Messages:
    139
    Location:
    Livermore, CA
    For the emissions codes there’s something where they aren’t fully cleared when you clear with an odb2 tool. Unhook the negative cable from the battery while you are changing the downstream 02 sensors - the 30 minutes or so it’s not connected should wipe the codes.
     

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