Stupid Question - Sorry -

[89vncommy]

Ok .. Well .. Here goes...

This is pretty much my first Commy .. Well first Auto anyway ...

My question is, on the auto tranny, there are 2 drives. 1 with a box around it, and 1 without. So my question is which one is overdrive ??? And if I want the best fuel economy, I would make sure I drive out of overdrive, is this correct ... ???

Sorry for such a dumb question, but as I said this is the first time I have had a car with this as an option.

[90VN55]

i thought it was like this
blue one is overdrive
and white one is drive
so 1 is 1st gear
2 is 2nd
white D is 3rd
and blue D is 4th

so blue D would give u better econemy cause it wont be revving as high cause it will go into the last gear

i hope that makes sense

[Emackulation]

Yeh, Adam is correct.

[pandaman]

Ok .. Well .. Here goes...

This is pretty much my first Commy .. Well first Auto anyway ...

My question is, on the auto tranny, there are 2 drives. 1 with a box around it, and 1 without. So my question is which one is overdrive ??? And if I want the best fuel economy, I would make sure I drive out of overdrive, is this correct ... ???

Sorry for such a dumb question, but as I said this is the first time I have had a car with this as an option.

Mate, no such thing as dumb questions, only dumb people Just kidding. Anyway, as the other fellas have said, white D is 3rd, Blue D is fourth. It's just like any other 4 speed auto except for the weird letters, dunno why holden did that.

An overdrive gear is one where the output shaft of the box spins faster than the input shaft. 4th (or blue D) is the overdriven gear in that box, with a ratio of 0.7:1, meaning that for every 0.7 of a revolution of the input shaft, the output shaft turns once. That's your top "cruising" gear for the open road.

Some people like to drive around town with the shifter in 3rd so that the box won't select fourth, this can give more responsive kickdowns. So if you're driving around at 60km/h in 3rd and put the boot in suddenly the gearbox kicks straight down to second. If you were in 4th and put the boot in, the gearbox selects third and then second giving a slightly slower shift. If you're just doing that at around 60km/h it's not likely to make a difference with fuel economy, but if you're holding 70 or so km/h in third for extended periods of time fuel economy may begin to suffer. (sounds real nice in my car though)

Sorry if this isn't very coherent, beer o'clock started around an hour ago.

[89vncommy]

Cool thanx guys... Some great info there...

[1991_Vn2nV]

White D is best for fuel economy around town... I cant explain this shit, but look up torque converters on howstuffworks and it will basically explain it for you. Its the same reason why a manual gets better fuel economy, despite normally doing more revs than an auto does.

[xcop5l]

also the t700 boxes have a lock up clutch in the converter which provides direct drive in 3rd and 4th after about 60kph grate for hiway

[smokey_dj]

yeah i pretty much find after about 70-75 slip it into overdrive (blue D) and she just rols along without much to say but fuel stays nice and lengthy
(till you go bigger diff ratio and shift kit then it starts to go back down hill :P)

[89vncommy]

Thanks all ... I think I am going to change all my plugs, and leads...

Is there any special brand I should look for in the leads, or just head down to supercheap and pick what ever they give me ???

[savage1987]

Most people tend to go with some sort of aftermarket leads, but I've been advised the Holden ones are among the best . . .

As for plugs, go for NGK Iridiums - that is, if you don't mind spending $20 PER PLUG as opposed to $20 for a whole set . . . I like them though!

[89vncommy]

Cool thanks.. Have NGK Iridiums in my other car & Bike... They are good pulugs and well worth it...