Discussion in 'GM Powertrain' started by GM_Guy, Aug 15, 2007.

  1. GM_Guy

    GM_Guy New Member

    someone told me that you should not use the "OD" position for in town driving, that you should use the "D" position instead. is this correct, or is either one acceptable? I have been using the "OD" position for a long time without issue
  2. Dj Friction

    Dj Friction New Member

    Well.....I have always driven in matter city or country. I do however never use OD when pulling the trailer.

    Overdrive will only shift at speed and Rpm's....I guess the reason is to limit the overdrive shift and lock-up position in city driving????

    Just a Thought!!!
  3. GaryL

    GaryL New Member

    When I was driving my 89, I always drove it in D around town. It had 3.08 gears and just seemed to lug too much in OD around town.
  4. GM_Guy

    GM_Guy New Member

    my burb has factory 3.73 posi, so I figured using OD around town would help mileage
    I would never use it for towing
  5. 84fiero123

    84fiero123 New Member

    Around town you may notice at times the trany shifting in and out of over drive quite a bit. That will kill your mileage, in town.

    It will also give the trany excessive work. In a town like Boston you would never go into OD even if it was engaged.

    Now a small town like mine it jumps back and forth a lot, little traffic except during tourist season.

    I have a question for ya.

    How come during deer season you can shoot the deer, but during tourist season you can’t shoot the tourists?
  6. GM_Guy

    GM_Guy New Member

    good question

    so, I'll start using "D" instead :)
    Last edited: Aug 15, 2007
  7. tbplus10

    tbplus10 Super Moderator

    Because Venison taste much better than tourists. The rotting tourist carcases just go to waste.
  8. TA Dave

    TA Dave New Member

    As long as the tranny isn't "hunting" for a gear leave it in OD.

    And for the record, I always tow in OD (28ft race trailer around 10K lbs). Again as long as it's not hunting for a gear, and the tranny is in good shape, you'll be fine.

    A friend has a 97 GMC 3500 Dually with a 7.4/4L80E and has towed in OD since new. He's got 140K miles on it now and pulls a 44ft 5th wheel race trailer.

    This is for 4L80's, the 4L60's could be too weak to tow with in OD.
  9. ChevyFan

    ChevyFan Administrator Staff Member

    I've never had much experience with any OD tranny shifting or hunting for gears. The manual makes it pretty clear that you should never tow anything when in OD, and I take that a small step further, I turned off OD when hauling anything more than a couple of passangers.
  10. Crawdaddy

    Crawdaddy Moderator

    I have yet to come on a time when I needed to pull it out of OD. I've never towed with the Burb yet, but if I did, I'd pull it into drive then, but around Slidell, I run in OD and it never seems to hunt for gears while in traffic.
  11. stockchevy1983

    stockchevy1983 New Member

    how do u know which tranny u got? only thingi was told was if i had a heavy duty tranny it would be 2 humps on the pan which is what i have. its a 98 yukon
  12. Chevy1997

    Chevy1997 New Member

    od good for highway

    Well, it´s true, od off kill mpg specially at town. The system "OD" consist in "metaforically" order to on board computer to change the shifts (or gears, i don´t know the difference) quickly to arrive a "D" position as soon as possible. Homever the transmission will do an excesive use a long of life and it´s probably to fault or bad fuction. In resume, for my experience and friends with gm trucks recommend me that i must to use at town the truck with od off.
    OD was builded with the mission to grow up the mpg in usa trucks.

    Well, is my inexperienced opinion. I hope to help somebody.

    From the south of Cancer trophy...

    Viva Chile Mier....

    pd: 84fiero123 you are working in a mine?
  13. 95CTburb19

    95CTburb19 New Member

    I notice my 95 burb hunts for gears in overdrive but I have no drive. 3 would be a different story all together correct?

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