| From | Message |
black00
Dodge Dakota
JOIN HERE
9/24/2004
10:13:48
|
 Subject: overdrive
IP: Logged
Message:
does turning off overdrive make u accelerate better?
|
99bludak
Dodge Dakota
JOIN HERE
9/24/2004
11:01:32
| RE: overdrive
IP: Logged
Message:
Yes. This is because it is a lower gear ratio with it off. In overdrive, you usually downshift when you mash the gas, then you get the power to really accelerate. You will use more gas though going highway speeds with OD off.
|
TheMonk
Dodge Dakota
JOIN HERE
9/24/2004
15:17:43
|  RE: overdrive
IP: Logged
Message:
Speaking of turning off OD...I have a question: If you are only city driving (stop and go, top speed of 40-45mph), should you keep OD off? My dealer/salesman told me to always keep OD on unless you are towing or going up/down large hills. My father has 2 Dodge Rams, he says both of them get better mpg in the city(side streets) with the OD off because the truck doesn't have to shift in and out of OD. What you think?
Thanks,
Mike
|
99bludak
Dodge Dakota
JOIN HERE
9/24/2004
16:36:32
| RE: overdrive
IP: Logged
Message:
I also try to keep my truck out of OD during constant driving under about 45mph. It is better on the transmission because it doesn't shift as much. Everyone probably has their own opinion on this subject, but that is mine.
|
gen1dak
Dodge Dakota
JOIN HERE
9/24/2004
22:07:31
| RE: overdrive
IP: Logged
Message:
To clarify, turning off the overdrive will not help acceleration from a standing start, but will help if you're cruising.
You probably will get better mileage around town with the OD off because the engine will probably be lugging below it's best engine speed. Turning it off will let the engine run in the preferred "sweet spot" of the power band for best efficiency.
|
.boB
Dodge Dakota
JOIN HERE
9/24/2004
22:15:21
| RE: overdrive
IP: Logged
Message:
I've tried driving around town with it off and on. There's no differance in fuel mileage. You'de think there would be. However, the truck feels better, because the engine is always up in to the powerband when I want to accelerate, and it helps with engine braking going down hills.
|
TheMonk
Dodge Dakota
JOIN HERE
9/25/2004
08:31:30
|  RE: overdrive
IP: Logged
Message:
I wish Dodge made an OD button that didn't reset to the "on" position when you turn the ignition off and back on again. Fortunately, I can live with that though.
|
Ken
Dodge Dakota
JOIN HERE
9/25/2004
09:11:31
| RE: overdrive
IP: Logged
Message:
Couple of things here with the OD that have been beaten around, but not fully explained
1) If I understand correctly, with OD off, the transmission will never shift into 4th gear. Which is why you won't OD on while driving highway speeds
2) It changes your shift points at *partial* throttle. So, in city driving, with OD on, it's going to shift a lot earlier and more often on you. If you baby it, it'll probably shift around 2,500 RPM or thereabouts? Under WOT, the shift points are the same. Most guys that run their Dakotas in the 1/4 will turn it off so it doesn't shift into 4th gear on them.
Personally, I prefer it off unless I'm driving highway, it just drives so much better IMHO. Plus, you don't have it shifting from 4th gear down to 2nd when you stomp on it.
|
.boB
Dodge Dakota
JOIN HERE
9/25/2004
11:38:02
| RE: overdrive
IP: Logged
Message:
Seems like I heard of a black box that changes the default from on to off on start up. Can't remember who sells it, though. It's out there if you can find it. Call one of the performance parts dealers that advertise on this board, I bet they would know.
|
black00
Dodge Dakota
JOIN HERE
9/25/2004
14:39:06
| RE: overdrive
IP: Logged
Message:
so in a 1/4 would it make sense to turn it off or keep it on?
|
gen1dak
Dodge Dakota
JOIN HERE
9/25/2004
15:00:18
| RE: overdrive
IP: Logged
Message:
As far as I know, the shift points do not change on any of the 3-speed with OD transmissions. This is controlled by the throttle kickdown linkage. Now, on the so-called 5-speed autos, I dunno, haven't gotten into them yet.
As for the reset button for OD, just swap wires...thus reversing polarity. Then, it'll default opposite of what it does now. I haven't done this, but I remember reading it somewhere. Hell, I don't know if it'll work, but it's worth a shot.
|
Ken
Dodge Dakota
JOIN HERE
9/25/2004
16:34:31
| RE: overdrive
IP: Logged
Message:
In the 1/4, pretty much everyone will tell you to turn it off. But really, if you don't get going fast enough where it won't shift into OD, than it doesn't really matter. But, most Dakotas will probably be pulling 80-85mph in the 1/4 if they're mostly stock (except for maybe some of the really heavy quad-cabs 4wd). There are some dakota owners that will hit the rev limiter in 3rd while running the 1/4 (mind you, they're not stock at all).
The shift points are really controlled by the PCM from my understanding. One of the things the Mopar PCM does is change raise the shift points, specifically under WOT. Like I said, try a gentle accelleration with the OD off, than do it again with the OD on. I believe it shifts at different times.
|
boydzz
Dodge Dakota
JOIN HERE
9/25/2004
22:03:36
| RE: overdrive
IP: Logged
Message:
Here's my question on the topic...
I have an '04 4.7L with the 5 speed auto. This transmission will downshift into a higher ratio second gear, which is a differnt ratio than the first to second upshift. My question is does the O/D off buttion have any influence on what ratio second gear is used? Meaning, with the O/D off will the truck upshift into the higher ratio second gear? I haven't tried it...it never crossed my mind until reading this thread. Anyone have any knowledge on the subject?
|
gen1dak
Dodge Dakota
JOIN HERE
9/25/2004
23:23:12
| RE: overdrive
IP: Logged
Message:
Ken, the Mopar PCM does not change shift points per se. It does, however, increase redline engine speed, and this will allow the engine to rev higher in each gear at WOT...IF the kickdown cable is adjusted to take advantage of this. So, WOT shift points are higher, but only because the engine is allowed to wind higher. Again, part-throttle shift points are not affected.
boydzz, no, the 2nd gear prime downshift happens when heavy throttle is sensed by the PCM. It has nothing to do with the OD. Shift schedules will be adjusted by the PCM based on sensor inputs relative to operating temperatures of the tranny fluid. (And if you think about it, why else would they be changed? Just because you want to lock out overdrive?) This is done to extend the operating life of the tranny in extreme conditions.
|
| | P 1 |
|
Post a reply to this message:
Username Registration: Optional
All visitors are allowed to post messages
|
