Lately this has caused me to wonder..

I do mostly city driving, ~90% and a lot of that is hilly stop and go driving. I"m also real easy on the throttle and I pretty much drive speed limit (50-60km/h), which I believe is around 35mph?

Anyways, I typically drive in "D" w/ OD on, but at those speeds and with my light foot, my engine is only revving at around 1,200-1,500rpms, albeit at a constant as I'm upshifting faster and getting into the 4th gear faster. At those rpms, the Max sounds like its under-revving. Would that be bad for it?

Just curious to know at city SPEED LIMIT speeds, which gear should I stick with? "D" w/ OD on or "D" w/ OD off? I've driven in "2" a few times but I'd have to constantly apply throttle to keep speed. "D" w/ OD off seems to be the happy medium, with my rpms at around 2,000 though..But what do you guys say?

Also, would there be any problems associated with turning on and off the OD button while in motion? I'm assuming that it is electronically controlled, so it wouldn't wear down the transmission or torque converter..Just trying to prolong the life of the tranny and engine..

Sorry for the loaded questions. I checked out the FAQ thread but it says nothing about harm to the mechanics

 

hmm..all i'll say is that I only use o/d on the highway...i have a habit of starting the car and turning off o/d right away... when getting on the highway i turn it on. . .
It doesn't do anything to your tranny...you just have 3 gears instead of 4.

 

OD is 4th gear and I only use at 40mph+. You said you drive in sometimes, does that mean you shift the gears yourself? Either way you want is fine I didn't notice any gains/losses either way. It just means your tranny has an extra shift to make.

 

I heard its not good to downshift while in motion w/ an auto and I stick to that since when I do drop the o/d while moving the tranny seems to jerk a little, but upshifting from 2nd to 'D' to 4th is fine. I dont want to take any chances with my 88k luxury smooth shifting automagic. but its up to you.

 

No I don't shift the gears myself. I'm just curious because with the short trips I do along with the medium and slow traffic and the hills and my light foot, I find that I'm under-revving the Max a lot and the shaking and the noise bothers me some..

"D" w/ OD off seems to be the best compromise though with regards to the rpm band as I'm in the 2,000 range..

 

It jerks because it's dropping down a gear and giving it more power O/D was designed to be used while in motion, like when you want to overtake another vehicle or to help slow down on zig zaggy mountain terrain. Been using mine this way for the last 133000km's (82000miles) and it still works like a new one

As for city driving, I drive with O/D on. I cut it down to 2, or even 1, in slow moving traffic to stop it from shifting up and down all the time and to help in slowing down as well. No damage has occured yet

 

i always shift down while in motion to slow down, i have 76k on my 98 SE and no problems yet...with overdrive off it revs your engine higher...right

 

If you have a soft foot and get into od at 50-60 km that should be fine as long as you arent towing anything or going up a steep hill. If you are loading the engine at low rpm then you may get some knocking and carbon etc. I let my od do its thing and always cruise the city at 60 km for better mileage. If I feel the engine is loading I just push a little harder on the gas and it kicks the od off on its own. Take her on the hiway from time to time and blow the carbon out of it, that will keep everything nice and clean, dont be light on the gas when you come up to speed though, stomp on it and blow all that carbon out the tail pipe, the guy behind you will love it

 

OD was designed for the highway not passing people. It only jerks(for example) when you're doing 20mph in 3rd and go WOT, then it down shifts. If you're in 3rd and put OD on your acceleration in 4th is weaker than in 3rd. And what's the point of manually shifting down a gear, you're just adding additional wear to the tranny

 

i get just plain ugly fuel economy (15mpg city 20 highway)...

OD on or OD off.... anything to do with fuel, if so how much... thanks

 

yeah, thats what I was trying to say, but came out wrong, lol. What I was trying to say was that I turn O/D off when I want to overtake someone

 

turning the od off when driving city and in traffic is fine. it helps by keeping our wonderful auto ecu's from gear hunting all the time, as they will always try to reach 4th gear even if your only going 30mph or so.

with the od off you will use more gas as you will be running higher rpms.

downshifting isnt going to hurt your car, but it certainly dosent help anything. this is of course in moderation, if your driving your auto like a 5spd your asking for trouble.

if your worried about your transmission, go out and buy a transmission cooler, they are cheap insurance and very easy to install with basic tools and knowlege. in fact there is a fantastic write up on it here on the org in shoptalk.

good luck

 

Dam are you serious about the whole {OverDrive Off = More MPG?}
Can anyone else confirm that?

 

It's BS. I drove the car for over a year with OD on. For the last 7 months or so I've turned OD on only on the highway There is NO DIFFERENCE. My fuel economy is just as terrible as it was before..

 

constant use of downshifting in auto can grind up the gears so dont bother trying, the feel of it is nasty too. if youre downshifting to slow the car down, thats no good for the transmission. why would you wanna do that anyways... use common sense.

 

heh, been doing it for the last 4 years that I've known the car (133000 odd km's) and I've noticed no decline in my transmission's health, still works like it did when I first got it

 

Absolutely correct...believe me, it's WAY cheaper and easier to replace brake pads than transmissions. Unless you're going down a long steep hill, use your brakes and not your tranny...

 

by od off i mean that you can see the od light in your dash lit up

 

check you fuel injectors, this might be causing your problem

 

your overdrive trans was designed to operate in the normal 4spd (o/d on) mode during all normal driving conditions....the only time you need to turn the o/d off (light on dash is on) is if the car is hunting for the correct gear....example very hilly roads with a heavy load in the car.....if your car is constantly switching from 3rd to 4th and back again switch the o/d off.....other than that leave it on....

 

I actually did that a few hours before I posted that message. The front 3 are running awesome, very fast ticking sound. The only rear one I could get too, the one on the left side of the engine bay, was ticking slower like it was clogged up. The other 2 I don't know. I'm doing some research and plan on doing that in the spring. Thanks anyway dude.