Only recently have I been driving around in D more than OD b/c i like the throttle responce. I don't liek the overdrive feel, too much luxury, D feels more 'sports car' to me. Anyway, what woudl be the downsides to driving around normally in D than in OD? How much gas would I be wasting and would it put more stress on the transmission, engine, or anything else? Any input?

 

Well, it will definitely use more gas and put a lot more stress on the transmission and engine because they have to work harder. I have a couple of friends who also like to drive around with the gear in drive instead of overdrive. Of course they have more money to throw away than I do so they can afford the repairs. When in overdrive, the car is normally in the drive gear until the speed reaches about 45MPH, then the overdrive will kick in and change the gear ratio so there won't be as much stress on the engine and transmission. Even the manufacturers don't recommend using drive all the time. Just a thought!!!!!!!!!!!!!

 

uh imagine if you had a bicycle with only 4 speeds and you limited yourself to the first three

thats what driving in D is

OD is just 4th gear and you are not allowing yourself to get into it.

Obviously your car is going to be more responsive in 3rd gear at the same speed as it would in 4th gear because the rpms will be higher and closer to the powerband. As far as it wearing out your transmission, no it wont. It will just make your engine rev higher all the time which will cause it to wear faster since its making more revolutions for the same trip. It will also consume more gas.

Is it going to screw up your car? probably not, you are just going to waste gas more than anything else

 

Pablo is dead on. OD will keep your rpm's down hence better MPG and less wear. OD is when your output drive is spinning faster than your engine crank.

 

maybe I am just dumb, but driving the car in OD vs. D should have absolutely no effect on your responiveness. If the tranny is in 4th, and you punch it, your transmission should downshift to 3rd assuming you are not going to fast for it to do so, which would be like atleast 80-85 mph. So I wonder if your tranny is working quite right. That just doesn't add up to me. Like they said above, your just cutting' out one gear. Be no different as if you have a T56 and you just refuse to shift into 6th. That shouldn't effect gears 1-5. Am I off track?

 

it does take time for the trans to down shift from 4 to 3, which is why it feels like a better response when you stay in 3rd. i think thats what their saying. however, you can't argue with the fact that higher rpms over a long period of time will cause more wear.

 

What is meant by more responsiveness, is that before it shifts down, you are running higher RPMs. THis puts you higher into the power band, so when you accelerate a little bit, it feels more pwerful thatn if you were to accelerate a little bit in OD.

 

That's true, I dunno if it is worth the wear and tear and the gas though.

 

While I won't argue the point that driving around in D most of the time will increase engine wear, I will point out that its pretty much insignificant in the grand scheme. One trip down the 1/4 mile would wear an engine more than an entire year of 1:1 driving. A single dry start (car sitting for extended period) would also be comparable.

I've never heard anyone ask for advice on going from a 3.08 rear gear to a 3.73 and someone come on and say "Yeah you'll get better acceleration but you're engine will wear faster"

I've been driving around in D at all times for years with the exception of high speed highway driving. In fact, my 1985 owners manual RECOMMENDS leaving the shifter in D for most normal driving, and only selecting OD for highway cruising.

If anything most normal driving is best done in D. Most driving is done right around the 3-4 upshift/downshift speed, around 40-50mph. The constant hunting in and out of OD will wear your trans considerably, not to mention being quite annoying.

 

If you are doing city driving with stop and go traffic, why not keep it in Drive (D). You are not going to over 40 MPH to kick into OD and if you want perfomance keep your foot into it and the tranny will stay in (D). However; if you are in a area with speed limits over steady 40 MPH by all means put it in (OD).

 

Why not just leave it in OD all the time, the tranny will take care of it's self

 

Because of the responsiveness. It really does make a difference, the 4 to 3 shift takes a while.

Also because of that.

 

Exactly what I do, I usually stay in 3rd around town, or when traffic won't let me get over 45 MPH, then as soon as I get up to about 45-50, I kick it into OD.

When I am getting on the freeway I am almost always in 3rd, for the on ramp and the first 1/2 mile or so on the freeway, so I can get over to the fast lane (I know what you mean about responsiveness, 3rd feels so much more peppy and gets you infront of people ) But once I'm where I want to be, and traffic is flowing nice and quick I jump into OD and keep on going. If I see brake lights ahead, or about to exit the freeway I kick it back down to 3rd, helps me slow down a bit, so I don't have to lay on the brakes so much.

I used to just stay in OD all the time, but after driving around in 3rd, I like it a lot better. My tranny shifts early at light throttle, i'm talking 1700 RPMs and it shifts, which I don't like, especially if it's going into 4th gear (OD)... 35 MPH in OD takes my engine to idle.

One thing I wonder tho, my car feels like it down shifts differently when in D compaired to OD. OD seems to want to stay in the higher gear, and takes my engine to idle all the time, before downshifting, and doesn't even want to down shift then. D seems to down shift a bit earlier, and seems to be happier down shifting all together. Anyone else experience this?

 

guess I am just not that much of a stifler. Unless I seem some hungry ri@#, there is just not much reason to get on it all the time during normal' driving.

 

I don't shift into OD until I am moving alteast 55-60. I have noticed that the 4-3 shift takes forever to happen (like 5 seconds). If I am in third and floor it, I am at 85-90 before the trans would have even downshifted 4-3. The funny thing is that in OD it shifts 3-2 instantly or even 2-1 it feels about the same as being in D. The only thing that changes is that in OD it almost refuses to do the 4-3 shift. I know that I need to change my governor to about 5,500 rpm or so (4,300 now) and that should help responsiveness and performance.

On trucks and SUVs not to mention in my van manual GM recomends driving in D not OD when you are in the city, heavily loaded, or towing. I also get 17-18 mpg in D but only 14-15 in OD in the van so I just keep it in 3rd. I am going to swap to 4.10s or 4.56 so that I will turn the same rpm in OD that I currently turn in D. I am only running 2,500 RPM @ 70 in D and 1,700 in OD. I bet in my case the engine is actually lugging below its powerband and actually causing more wear than D would.

 

Get a new tranny!!

 

Agreed... 5 seconds to shift into OD is WAY too long.

As for driving habits, I personally believe the trans and engine parts are under more torsional stress in OD at low speeds, so that's why you would keep it in D until hitting ~45mph. If you slam the gas but only enough to keep it from downshifting, it will put some strain on moving parts. You ever try pedaling a bike in its highest gear from a start? It's damn near impossible, but you could probably put enough strain on the pedal or chain to break them.

OD just allows you to go faster with lower RPMs, giving better mileage and reduced wear from high RPMs.

 

you mean torsional shear. sorry, couldn't resist a good mechanical engineer joke

 

Doesn't converter lockup only occur in 4th gear? If so driving in 3rd gear will build up a decent amount of heat considering the converter is slipping when it should be locked up. I might be wrong but I was thinking that is also another reason (first being better final gear) why you get better gas mileage in OD than D.

 

TC locks up in 3rd as well at 4th

 

I drive around in D unless im doing atleast 55MPH. I dont know why some of you say it takes a while to kick down to 3rd when you mash it? I have no problem, i mash it and it drops down a split second after my foot hits the floor.
I also think it has a lot to with your rearend ratio?

 

Mine takes time to downshift not upshift. The upshifts are quick and crisp with no slip.

I think the downshift thing has alot to do with the calibration. There are many different governors, tv sleeves and plungers, springs etc. Maybe I need to go to 9C1 stuff.

I think I need to go into the valve body an replace the TV plunger spring.

The early 700r4s lock in every gear except 1st. I get lockup in 2nd, 3rd, and 4th if the vacuum is high enough.

I know about the bicycle thing because one time I broke a chain starting off in a high gear.

 

yah i too drive around town without using OD because i like the feel and sound of the exhaust....actually since i have a megashifter i sometime ratchet through the gears which gives me the best responsiveness

 

I drive around town in D and in OD on the highway. There seems to be less wear and tear on the tranny since it doesn't have to shift as much and keep locking up the converter.