daily driving question
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TECH Apprentice
Joined: Jun 2007
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From: Raytown,MO
daily driving question I have a automatic 99z28, a guy that owns a transmission shop told me that I should use just my regular drive when I am in the city just driving around and use my OD only on long trips it will help me save alot of gas is this true. I noticed the regular D give me a little better take off.
OD on the highway will give better fuel economey but I dont think there would be any difference or improvement in economy around town in D. I tell people just leave it iN OD
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FormerVendor
Joined: Oct 2006
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From: D-F/W
If it has a stock tune, the PCM will allow the converter clutch to lock up in third gear, that definately helps fuel economy and may account for the recommendation from your local shop.
But, anytime you can get it into overdrive the fuel mileage will be that much better. There aren't too many reasons I would recommend a customer to not use overdrive for city driving.
g
But, anytime you can get it into overdrive the fuel mileage will be that much better. There aren't too many reasons I would recommend a customer to not use overdrive for city driving.
g
You here from both sides of the isle on this one but the overun clutch is on in the D position and not the OD position and can help support the input sprag.
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i use regualar drive for city driving just not to lug the tranny and motor seems to keep it a tad bit cooler also on my temp guage also keeps the tranny from having to upshift and downshift so much
i just keep mines in " OD" and i just let the tranny do the work. i dont manually shift or anything. plus i think im getting good gas mileage is cuz of the sporty 2.73's i have.. 
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what your friend is reffering to is gear ratio....if you have stock 273 gears drive is way better in town...mine had 273s stock...around here od was useless....i actually get better city mpg with 3.73s...i can use od now....as for racing I use D...
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in the owners manual, i believe it says to keep the car in OD unless youre driving in the hills or traffic is really crowded...something like that. i keep mine in OD all the time. only time i put it into D is when i go through the mountains to go fishing or during really bad rush hour traffic. 
Originally Posted by Ratchthed
If it has a stock tune, the PCM will allow the converter clutch to lock up in third gear, that definately helps fuel economy and may account for the recommendation from your local shop.
But, anytime you can get it into overdrive the fuel mileage will be that much better. There aren't too many reasons I would recommend a customer to not use overdrive for city driving.
g
But, anytime you can get it into overdrive the fuel mileage will be that much better. There aren't too many reasons I would recommend a customer to not use overdrive for city driving.
g
i have a custom tune with a 3rd gear lock up with a 3800stall but i drive it in od anyway 4.10's own me.
FormerVendor
Joined: Oct 2006
Posts: 3,123
Likes: 3
From: D-F/W
I have posted here several times recently that we ordinarilly delete L/U in 3rd gear. There are several combination specific conditions that go into that determination... it is very vehicle specific. My experience has been tempered with many, many different cars and lot's and lot's of seat time with the guys next door at Xtreme Horsepower. We have worked together for a very long time putting together tuning mods that provide excellent driveability when compared to stock tunes after significant engine and drivetrain mods have been implemented.
Having 3rd gear L/U is not entirely a bad thing at all!
The key to remember about TCC L/U is it was originally designed to contribute to fuel mileage. In many of todays high powered DD combinations it is actually a detriment to driveability. Custom transmission tuning is required in many, many cases where the engine horsepower output, gears and torque converter have been upgraded from stock. Again, it is very vehicle / combination specific.
g
Having 3rd gear L/U is not entirely a bad thing at all!
The key to remember about TCC L/U is it was originally designed to contribute to fuel mileage. In many of todays high powered DD combinations it is actually a detriment to driveability. Custom transmission tuning is required in many, many cases where the engine horsepower output, gears and torque converter have been upgraded from stock. Again, it is very vehicle / combination specific.
g
Originally Posted by Ratchthed
I have posted here several times recently that we ordinarilly delete L/U in 3rd gear. There are several combination specific conditions that go into that determination... it is very vehicle specific. My experience has been tempered with many, many different cars and lot's and lot's of seat time with the guys next door at Xtreme Horsepower. We have worked together for a very long time putting together tuning mods that provide excellent driveability when compared to stock tunes after significant engine and drivetrain mods have been implemented.
Having 3rd gear L/U is not entirely a bad thing at all!
The key to remember about TCC L/U is it was originally designed to contribute to fuel mileage. In many of todays high powered DD combinations it is actually a detriment to driveability. Custom transmission tuning is required in many, many cases where the engine horsepower output, gears and torque converter have been upgraded from stock. Again, it is very vehicle / combination specific.
g
Having 3rd gear L/U is not entirely a bad thing at all!
The key to remember about TCC L/U is it was originally designed to contribute to fuel mileage. In many of todays high powered DD combinations it is actually a detriment to driveability. Custom transmission tuning is required in many, many cases where the engine horsepower output, gears and torque converter have been upgraded from stock. Again, it is very vehicle / combination specific.
g
