2004 Overdrive

[dh271]

I just bought 2004 Impala this week. It has the 4-speed overdrive. Is it best to leave it in the overdrive position in slow city driving or is the "3rd gear" position same as regular drive?

[maxwedge]

You an use 3rd, which is like direct drive, in driving under 45, I do this a lot.

[dh271]

Ok, I did that last night and it did great, Thanks!

[impalalover]

Originally Posted by dh271

Ok, I did that last night and it did great, Thanks!

what difference did you find by just driving in 3rd instead of 4th with overdrive,i found mine harder on gas and when you go over 45-50 you have to put her in 4th anyway or she wont go into overdrive and will be holding back and be harder on gas

[phewop118]

By keeping it in 3rd, you are keeping your transmission from shifting into 4th and back into 3rd, which it will do alot if you are driving between 35-40mph (depending on axle ratio, could be a bit above 40). This helps the transmission by saving it from shifts and it makes the car more responsive because it doesn't have to downshift from 4th to 3rd for hills or slight acceleration.

[impalalover]

Originally Posted by phewop118

By keeping it in 3rd, you are keeping your transmission from shifting into 4th and back into 3rd, which it will do alot if you are driving between 35-40mph (depending on axle ratio, could be a bit above 40). This helps the transmission by saving it from shifts and it makes the car more responsive because it doesn't have to downshift from 4th to 3rd for hills or slight acceleration.

yes i agree with that but it will still burn a lot more gas then it normally would

[BNaylor]

Originally Posted by impalalover

yes i agree with that but it will still burn a lot more gas then it normally would

I agree. Unless you are smarter than the PCM module it is best to leave the shifter in 4th - OD and let the powertrain management system do the work for you even in most city driving, especially for overall fuel economy. However, it doesn't hurt to manually downshift to 3rd in hilly/mountainous terrain or when you need the responsiveness. The other feature the autotransaxle has is the torque convertor clutch (TCC) will lock up at speeds above approximately 45 mph for additional fuel economy. The TCC will only lock up in 4th - OD. I seriously doubt you will get better overall fuel economy just by leaving it in 3rd.