O/D off on an Automatic & Manually Shifting

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On another auto forum, I was reading a post that talked about how it's good to turn overdrive off when driving locally. Is there any negative impact on a transmission when you turn O/D off? My thought is let the AT stay with O/D on and let it decide what gear to be in. I never really gave it much thought. I've only driven manuals the last 20 years. In a mountainous/hilly area or when towing I can see the need to turn it off, but not for city driving. Modern transmissions are fully computerized, so they are much smarter at deciding when to use overdrive than you or I.

This was one of the comments:

"I manually shift mine all the time, in 3rd for around-town and into 4th when running a bit faster but not quite able to open it up for full highway cruising. According to my AutoMeter trans temp guage, it does not appear to change anything at all temps-wise and I find the throttle response and smoothness to be greatly enhanced. My trans usually runs around 155 to 160 indicated unless crawling through town in hot weather with the AC on, like today, where it appeared that a movie or TV sequence was being filmed downtown Baltimore and traffic was diverted into a complete snarl. A total Charlie Foxtrot but temps still hovered around 195 to 200."
 
You could drive without OD indefinitely and you wouldn't hurt the transmission. Your gas mileage would plummet but everything would function.

On my Tacoma, I'll drive in "4" when I remember to (and within the city) because it is peppier, but I'm habitually sticking it in "D" because that's the default.
 
There won't really be anything gained, and all you'll lose is fuel economy. That being said, my 8 speed is very quick to drop out of one of it's OD's when needed, and won't go into OD in sport mode.
 
Agree, that's what I figured. I don't see the benefit.
 
i bought a nissan frontier last year 2016 model. 244 ci V6 261 HP. O.D in a 4,220 lb truck. 3.31 rear gear. checked mine at 0-60 in 7.2 sec. 1/4 @ 15.7 sec these numbers are very aprox. my point is in town in O / D it pulls very very good down to 30 mph. O / D is a 0.839 ratio. much better than i thought a 244 ci in a 4,220 lb truck would.
 
If a car is geared poorly (too tall), the transmission might hunt gears and shift back and forth between OD and D a lot. That will create heat and put extra wear on the transmission. If you find the trans hunting a lot, turn off OD.
 
Driving within city limits often requires a lot of nuance with the accelerator to properly gap both the car ahead an adjacent to you. Selecting the appropriate gear gives you better response both on and off the throttle. When not driven aggressively, most cars today are programmed to get quickly into high gear to engage the lock up torque converter saving fuel.

Our Camry's 6 speed auto's accelerator pedal is real mushy in the 50-60ish Km/h range. Having it in S4 locking out the top 2 gears is much better. A simple tap to the right puts us back in normal drive when above those speeds.
 
This is such a 1980's conversation! When I was a kid I remember my Mom asking if she should drive her Astro van in OD or D. lol
 
Originally Posted by buster
Agree, that's what I figured. I don't see the benefit.



I disagree...

I had a Audi 2019 a5 whole traveling up north on vacation in Barryville NY...

That car was much better being driven in manual mode... Rpm in 5th gear going 63 mph was much better to drive. Enough power there if you needed it at 2300 rpm and when one pulled the foot completely off the gas pedal... Enough to slow the car down. Unlike it being in 7th gear and running 1200 to 1400 rpm and had was always hunting the lowest rpm it could find... Which is greatly annoying to me. I kept the car in 5th gear even cruising at 78 mph... And it was turning 3300 rpm. This was a 2.0 L turbo motor that was a 4 cylinder making almost 260 hp.
 
Good point. I'd rather keep it in 3rd then turn O/D off if I'm driving around town. Speed limits are usually 25mph.
 
Granted I'm talking about my older 89 GMC here but when I asked my mech about it I told him it liked to shift into OD at 35ish mph and around town it was constantly shifting in and out of OD he said it would be best to run it in D around town. I don't shift it in to OD until the speed limit is a least 40. At 35 in OD it only runs about 1000 rpm and seemed like it was lugging.
 
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If the trans is hunting between the gears turn it off otherwise it is an automatic.I am beginning the see that 90% of internet chat is B.S.
 
Manuals used to say to take out of OD if hunting was observed. Maybe that was only back when 4AT's ruled the roost, but it was pretty commonly seen.

Both of my automatics manage to handle 1-3 for the most part just fine. 4 and up though are a different story. Around town I'd rather have a bit more rpm for responsiveness. My truck really can only handle 6th on the highway, or on really flat ground. It gets better mpg at 50mph in 5th than it does in 6th at 60mph and faster. But that darn thing is in a race to get into highest gear possible, then you really have to get on it to convince it otherwise--just way easier if I block the gears I didn't want to use anyhow.

It's probably all in the trans programming--and the user's acceptance thereof--as to if manually shifting an automatic is "required" or not.
 
I keep mine in drive with O/D on all the time. If I'm going really slow I may just put it in 3rd.
 
It's always good to have options. In my case there are a couple of hills that are long and windy. Sport mode helps to keep the transmission in a lower gear especially when dealing with traffic. I also have the ability to manual shift.

Today's transmissions shift up quickly so if you are in a stop and go scenario on the freeway where you get up to say 15mph and have to slow down, sometimes the transmission doesn't follow. You can end up in fourth gear real quick and then try to accelerate from 10mph or thereabouts. Using Sport Mode helps.
 
I agree PimTac. Our 2014 Mazda 3 GT had a fantastic AT. Sport mode was great and so was the paddle shifters. Loved that car.
 
As you have been advised , I see no problem with turning OD off .

Last vehicle Dad had with OD was a small V-8 57 Ford w/ 3 on the tree . We had a small travel / vacation / fishing trailer . I remember he locked it out of OD when towing it , cotton trailers , grain trailers .

The car normally got over 20 MPG on the road , in OD .
 
Originally Posted by CT8
If the trans is hunting between the gears turn it off otherwise it is an automatic.I am beginning the see that 90% of internet chat is B.S.


can you point me to the ten percent, cause I'm not seeing it
 
I leave my automatic (4cyl Tacoma) in OD most of the time, the owner's manual says this is the default position. The compression braking is surprisingly effective even in overdrive gear. But if I anticipate going 40mph or slower for awhile, or I'm on a stretch of road with crappy timed traffic lights, I will lock out OD so it never goes above 3rd. In my local area, some roads are speed limit 35 and some are 50 so it's hit or miss.
 
Unless I am going atleast 50 for a length of time, I turn off the OD. The constant in and out of OD can't be good for the tranny.
 
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