Overdrive: How to use correctly. (MT guys do not read!)

Discussion in '2005+ Mustang GT 4.6L Tech' started by Terry, Nov 16, 2019.

  1. Terry

    Terry Junior Member

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    Hi esteemed Forum members.

    Manual overdrive (O/D) in my 07 has had me flummoxed ever since I bought the car over a year ago. Now I understand it is probably a locked converter situation or 1:1 ratio at which point the engine will begin to struggle when power is applied. Maybe my daily driver, an 04, 330k plus Honda Accord has spoiled me since O/D is really just a 5th gear that the gearbox runs in and out of as it needs to. I'm also very familiar with manual cars and truck gearbox's of the crash and 2 speed Eaton diff variety, so I guess I'm saying I do know how to change gears! Accordingly, an auto should be, and is, in most cases a piece of cake. Not so the S197 it seems.

    My current modus operandi is to run the car with O/D selected on. From a standing start the car moves up the gears until the speed allows it to gracefully drop into O/D. If I then brake say for another stop the gears drop down and we start again without O/D having to ever be deselected. The problem of course comes when running in O/D on a hill or conducting a passing maneuver both of which require the application of power. Absent minded and thinking I'm in my daily driver I increase power only to hear the engine struggle and even miss. A quick stab of the overdrive deselect button and .......blast.... the stab was too quick! A slower stab of the O/D deselect and the gearbox drops down, and I get some power just in time to clear that oncoming car in my now completely botched passing maneuver. This is kind a serious of course and I feel that maybe I'm not operating the O/D selector correctly. Yes, I know i should deselect O/D before commencing a passing maneuver, but muscle memory with my daily driver gets in the way of that sometimes. (which also explains why I occasionally hit the drivers door a couple times with my left arm during reverse selections, as I look for the gear change lever, thinking I'm in my RH drive Accord..Doh!).

    I know if I just ignored O/D and never selected it, the problem would go away, but engine noise and fuel consumption would increase. I do have a number of roads that I cruise control on so O/D is pleasant and less expensive running at 100km/hr or 60 mph. But, I just don't understand why it requires a manual deselection to drop down out of O/D when I need power and yet when the car slows down sufficiently to stop it doesn't? Again, I probably really don't understand what the operating parameters for the O/D are.

    Perhaps someone could point this hopeless case in the right direction before I spud in one day!!
     
  2. Laga

    Laga Member

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    "I know if I just ignored O/D and never selected it, the problem would go away, but engine noise and fuel consumption would increase. I do have a number of roads that I cruise control on so O/D is pleasant and less expensive running at 100km/hr or 60 mph. But, I just don't understand why it requires a manual deselection to drop down out of O/D when I need power and yet when the car slows down sufficiently to stop it doesn't? Again, I probably really don't understand what the operating parameters for the O/D are."

    Unless there's a problem in the transmission itself, and it doesn't sound like there is, you simply do not know how to drive the car properly. You are not applying enough throttle to make the trans downshift. Just give it more gas.
     
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  3. RedGt

    RedGt Junior Member

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    O/d off go gears.... and driving in traffic, o/d on higway.

    RedGT
     
  4. 07 Boss

    07 Boss Senior Member

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    I turn off the OD everytime I start my car. I tried to wire a OD monkey same as I did with the traction control (key in the start position triggers the Traction control and turns it off every time I start the car but still have the ability to turn it back on with the dash button) in there once but there is something in the start up procedure that turns it back on again after it gets turned off. Anyways I also tend to shift manually until I get some tuning software. I use a TCI shifter with the OD button on a B&M handle. I tried to get some tuners to set the shift points like I want but have yet to have any success. I tend to upshift at about 15 mph increments under light throttle and don't let it go into OD until about 70 mph. Yes I cruise in third gear at 40. Either way, once I get into OD and want it to downshift I do that with the throttle input. Now you just can't mash the pedal, you have to remember that gear selection has to do with a bunch of tables that calculate load vs throttle position vs engine rpm or whatever. But you have to be able to feel how hard your car is pulling relative to throttle position. I can get my car to shift down a single gear and then apply more throttle without it dropping into third. You must be able to master this as dropping from 5th to 3rd is super no bueno for our delicate transmissions.
     
  5. Terry

    Terry Junior Member

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    Well I don't disagree with you and that of course was the point of my post, that the O/D has me flummoxed. But I guess what you are unlocking for me here is the function of the O/D switch. I thought it simply unhid the O/D capability and once gearbox/engine parameters allowed the gearbox to select O/D there was no way of exiting that gear without turning O/D off. Needless to say, I've been driving the car like it's a semi automatic!! The engine shudder, vibration and sometimes missing that I get when load comes on while in O/D has reinforced this view that a manual deselection of the O/D is required since it wont automatically drop down. But you are saying that if I mash the accelerator the gearbox will drop out of O/D without any need to manually deselect? Seems a bit aggressive to simply maintain constant speed going up a hill and in a sense is actually a manual kickdown selection of a lower gear as opposed the gearbox computer recognising load and automatically kicking down. Which begs the question, what is the purpose of the switch? Why not just leave it in O/D all the time and let it automatically drop down as 'sufficient throttle' is applied to go up a hill or pass? I still don't think I understand the function and operation of the O/D as applied to this car?
     
  6. Terry

    Terry Junior Member

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    Wow, and I thought I had a semiautomatic fetish!! Good stuff 07 Boss, but this shifting down out of O/D without dropping to 3rd, seems a bit fraught. A delicate balance between enough power to activate the shift (what Laga said in his post above) but not so aggressive as to chop down 2 gears. Did not know the tranny was sensitive to this!

    If I applied your approach of not selecting O/D until 70 mph then I'd never need to select O/D since our speed limit nationwide is limited to 60 mph. Perhaps that's the answer. 60 mph dose seem a little slow for O/D. Maybe I jsut keep O/D off unless I deem flat road conditions allow it, and just switch select it on and off as needed. I might see how that works out for me!
     
  7. Juice

    Juice forum member

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    The O/D on/off switch in any Ford I've driven simply locked out the last gear. (a 4spd auto shifts up to 3rd, 5spd to 4th, etc) And I agree that the programming doesn't always pick the gear I want.

    From the vibrations and perceived engine miss, sounds like something is not quite right. But from the description, it sounds more engine related.

    Not like the old days of adjustable vacuum regulators or physical throttle cables where it was easy to tweak shift points. lol
     
  8. 07 Boss

    07 Boss Senior Member

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    IMO these little 3 valves like RPMs. My car only sees below 2500 rpm except when at a stop. The motor just seems happier when I don't let her lug around at 1800 rpms.

    Let me ask you something. With OD off and cruising in 4th, can you get the car to kick down into 3rd?
     
  9. tjm73

    tjm73 of Omicron Persei 8 S197 Team Member

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    Is this question/issue for real? Or is this a joke?
     
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  10. Terry

    Terry Junior Member

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    No joke tjm73 in which case I sense you have some comment hopefully helpful to make?
    So far I've learnt that the O/D will kick down if I mash the throttle which is something I was unaware of it since it hasnt done so in recent passing maneuvers! More gas seem to be the message. Note: my daily drive will hunt in and out of top gear smoothly with just a slight power changes.

    In contrast on the S197 the motor lugs when it doesnt change down so that just reinforced my apparent need to manually deselect overdrive rather than kick the throttle I'm away at the moment but when I get in the car next I will try pedal to the metal and see if it kicks down but if it doesn't it'll be a bit sickening but will either prove a point to me that I need to gas it or it might suggest there is an issue.

    Terry.
     
  11. Pentalab

    Pentalab forum member

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    What year is your car ? Is it a V8...or a V6 ??

    My 2010 doesn't lug at all in OD. (same 5r55s auto tranny used in 05-10 cars).

    You gotta put ur foot into it a bit...to get it to kick down into 4th. Is ur ATF level topped up?

    Manually shifting, here's what I get at 6000 rpm.
    1st- 70 kph.
    2nd - 100 kph
    3rd- 140 kph
    4th- 240 kph

    You want to avoid 5-3 shifts, and also 4-2 shifts.....and 3-1 shifts.

    Cruising at 80 kph on the hwy in OD, it's 1500 rpm..... and 2100 rpm @ 110 kph...(also OD).

    In 4th gear, its 2000 rpm @ 80 kph. 4000 rpm @ 160 kph. 6000 rpm @ 240 kph.

    Cruising @ 70 kph in 4th (OD OFF).....then mash the gas, drops down into 3rd gear... then a split second later, drops down into 2nd.

    Cruising @ 80 kph in 4th (OD OFF)... mash gas..and it drops into 3rd...stays in 3rd.
     
  12. skwerl

    skwerl tree hugger

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    Just get an aftermarket tune for the car. More power, better shifting, quicker throttle response. You have several good choices, I'd start with VMP.

    Do NOT buy any sort of bargain basement $99 tune or "Tunes for Life" from popular aftermarket parts retailers reselling lots of Chinese crap.
     
  13. Laga

    Laga Member

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    Whatta mean? I live for those!
     
  14. Pentalab

    Pentalab forum member

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    Agreed. I had Justin @ VMP tune both the eng + the auto tranny. With the Roush tune, the shift from OD down into 4th was god awful. Now they are all smooth. With the blower in the mix, the shifts have to be firmer + faster. VMP also unlocks the SCT-X3 so I can change individual RPM shift points, like 1-2, 2-3, 3-4, 4-5. ..... and ditto for firmness. He nailed it the 1st time around. 32 adjustments for the auto tranny in software. So u don't want some bozo tuning the auto tranny.

    The op needs to experiment a bit. He can also shut off the OD in a pinch.... then mash it...down into 3rd.... and off go, flying past everything.
     
  15. Flusher

    Flusher Member

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    Not really a direct comparison, but it still applies.

    Working for IBM in So Cal, I was logging around 1,000-1,500 miles per week. Let me tell you, that commute sucks! But, it gave me an opportunity to do some semi-scientific testing with my '96 5.2L Jeep Grand Cherokee.

    I found that 2,100 RPM is the sweet spot for that particular engine. 100 RPM or more, over/under 2,100 RPM increased fuel consumption. Interestingly enough, with the factory tires and gears, at 65 MPH, the RPM were 2,100. I have always kept this in mind while driving other vehicles on long commutes, when trying to maximize my economy.

    Now, I have an '05 V6 auto. It seems like I always have my foot in it, because I'm always late, I really don't have any MPH/RPM data. I travel CA 241 every day, where there is a 6% grade. The speed limit here is 65 MPH, but the traffic usually slows to approximately 50 MPH. My car will not downshift and lug all the way up that hill. If there is an opportunity to pass, and I mash it, it will downshift.

    I find it beneficial to click off the O/D because trying to climb that 6% grade in O/D lugs the engine HARD. Temperature climbs and I get some pre-ignition rattling if I don't.

    Driving my wife's '14 V6 manual, 6th gear is totally useless at anything under 94 MPH. I really haven't done any testing with her car, but it is really is not happy below 2,100 RPM.

    If I were going to mod her car at all, gears to bring the RPM to 2,100 RPM, at 65 MPH (common no traffic freeway speed limit), would be my first. I would try to find the "sweet spot" RPM for that car before making a final decision on final ratio.

    I think that if get your cruising RPM to where the engine is happy, the gear hunting will resolve itself. I don't think that there is any reason to disengage the O/D unless climbing a steep grade. I also think that, for a daily driver, the shift programming is pretty decent. However I believe the designed RPM are too low, pressured by emissions and economy standards.
     
  16. tw557

    tw557 Junior Member

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    I also have a TCI shifter and how do you have the handle work with a button in it. My OD button is located on the base of the TCI shifter. Not very convienient. I would like the button on the handle.
     
  17. Pentalab

    Pentalab forum member

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    The 11+ V6 cars get the 2.73 rear differential gears. Then u wonder why they lug in OD...going up a steep grade..at 50 mph.
     
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  18. Laga

    Laga Member

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    I had Lito turn off traction control. So it’s a non-issue for me.
     
  19. Terry

    Terry Junior Member

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    Thanks Flusher, you probably explained my experience better than me. Mines a 4.6 though but seems to do the same sort of thing.

    Ok well thanks everyone for you comments, thoughts and suggestions. I have a learnt that the car doesn't like low rpm and does have a tendency to lug. Coupled with some less than optimal shift regimes this may be the reason I am experiencing this apparent lack of automatic downshift. I have also learnt that engine/gearbox tune might help but that above all the car performs better at higher rpm and a bit more foot!! I also learnt some of the dangers with lugging in relation to band burning so again it seems keeping the RPM higher and turning off the O/D when looking for performance are both good strategies for passing maneuvers and for gearbox longevity.

    Thanks again.

    Terry
     
  20. fdjizm

    fdjizm Drag Queen

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    Hey just stopped in to say fuck your automatics.

    :roflmao:

    k bye!
     
    Last edited: Nov 19, 2019