i have a 93 z28 with stock trans and i am not sure when should i use overdrive and when i should use drive. i heard drive is more powerfull and overdrive is just so ur engine could run at low rpms and to save gas. should i drive on overdrive all the time or drive or only use drive when i race??? plz help.

All keeping it in drive really does is keep it from shifting into 4th (or overdrive). There really is no reason to keep it in drive when you are driving it normally.

so should i have it in drive when i race and then switch it into overdrive???

Just keep it in OD and let the tranny do what it wants. Usually at low cruising speeds people say to pull it back in D, like at 35-45 mph when the converter locks and is in OD and starts lugging.

thanks for ur advice but i get a whole lot of more power if i take off in drive then in overdrive.!!! or is it just me and its the same.??

thanks for ur advice but i get a whole lot of more power if i take off in drive then in overdrive.!!! or is it just me and its the same.??

It's just you. ;) There is no difference in takeoff power. Leave it in OD. The transmission knows what to do.

It's just you. ;) There is no difference in takeoff power. Leave it in OD. The transmission knows what to do.

x2. Nothing changes, there is absolutely no difference taking off in drive as opposed to taking off in overdrive. The difference will be when it is time to switch into 4th gear. If it is in D then it will stay in 3rd gear, and if is in OD then it will change into 4th.

Get a stall and some 3.73's if you want to feel a seat of pants difference.

My car in OD seems to shift at lower rpms then it does when its in Drive. Also if you dont come to a complete stop sometimes it will stay in second gear in OD... but for highway deff. OD.

put it in drive when your average speed crosses 40mph a lot.

in overdrive, you'll find it shifts between 3rd and 4th very often near 40mph, and gets a bit luggy when it's in 4th at that speed when climbing a hill at light throttle, and sometimes (because these cars are programmed for cruising economy) it takes too much throttle to make it kick back into third.

for example i live on a hilly winding road, where my speed varies between 30mph and 50mph (lots of crazy corners, hills, and straightaways.) if i use overdrive on that road, it hunts between 3rd and 4th a lot, and lacks power, because of the speed i need to maintain around some corners. so i use drive.

i also use drive in stop-and-go traffic. the less 3-4 shifts you get around non-highway speeds, all the better for the life of your transmission, and for power.

basically use your judgement for the road conditions. sometimes you just don't want to (or can't, for driveability reasons) go into 4th at light throttle. that's why there's a gear selector.

Isnt that what we call the deadspot?

so should i have it in drive when i race and then switch it into overdrive???

Do you 'race' on the street (like a dumb-ass) or at the track?

If on the track, then the answer is 'No'.

Most racers race in 'Drive' to prevent an upshift into 4th gear at the top end of the 1/4 mile......if that happened, it would slow down most cars just enough to lose a couple of tenths.

KW

put it in drive when your average speed crosses 40mph a lot.

in overdrive, you'll find it shifts between 3rd and 4th very often near 40mph.......

Steve,

That's the TC locking and unlocking.

The 3rd to 4th gear shift point at part throttle is in the 30-something MPH range.......about 33-35 mph.

The TC lockup point is right at 40 mpg......(+)(-)1 mph.

KW

my shift points must not be normal then

i can tell a tc lockup from a shift, and my light throttle 3/4 happens about 40mph

or maybe it was my poor mental conversion between mph and kph; apparently 60kph is closer to 37mph, not 40 like i was thinking

My 4L60/700R4 shifts into 4th around 40mph and the TC locks up around 55 once you let off the throttle a bit.40mph seems pretty low for the TC to lock up, thats like the speed most cars get into 4th.

i just leave it in OD and try and get all the mpg i can get.it just take a couple secs longer to shift down back to 2nd then u would in drive.thats about its no diff in performance wise or take off its just another gear.

if u running 55mph and a car gets beside u,and u have a gut feeling he wanna race u.drop it in D that will make u get into ur power band alil faster.since u only going from 3 to 2 not 4 to 2.

I wouldn'y downshift into second at 55mph. I would just down to 3(my selector goes 1,2,3,D, not 1,2,D,OD) and work from there.

I wouldn'y downshift into second at 55mph. I would just down to 3(my selector goes 1,2,3,D, not 1,2,D,OD) and work from there.

Its 1 2 D OD, in camaro's.

my shift points must not be normal then......i can tell a tc lockup from a shift, and my light throttle 3/4 happens about 40mph

My 4L60/700R4 shifts into 4th around 40mph and the TC locks up around 55 once you let off the throttle a bit.40mph seems pretty low for the TC to lock up, thats like the speed most cars get into 4th.

I wonder if this is one of the programming differences between F-bodies and B-bodies :dontknow: . I'll take your words on it that I'm wrong on this count.

Part of the reason I patrol this Forum......the possibility of learning what I thought I already knew :o .......

KW

On a 700R4/4L60, there is no programming, it's purely mechanical(hydra-matic shifting to be exact). They only used them in the 4th gen F-Bodies for the first year though, 1993.

On a 700R4/4L60, there is no programming, it's purely mechanical(hydra-matic shifting to be exact). They only used them in the 4th gen F-Bodies for the first year though, 1993.

True.

But the shift and lockup points are contolled by programing on the 4L60E.....which 90% of have have ;) .

KW

Ya, I was just saying that they aren't computer controlled on the 4L60/700R4's.

I wouldn'y downshift into second at 55mph. I would just down to 3(my selector goes 1,2,3,D, not 1,2,D,OD) and work from there.

well if you floor it it will do it on its own and its safe to do so cause the up shift from 2-3 is like 70ish not to sure exactlly what cause when that happens im to busy lookin at the road so i dont ram somebody plus the second my car shifts I get an instant 15 mph accel, shoulda got a car with a 4l60E that way you can just leave it in 1 and it will just rev like hell and shift up at 5700 only and be in its power band all the time i dont know about the non electronic 4l's but at about 125-130 and it shifts from 3-4 its one hell of a ride

That also depends on your rear gears, 5700 RPM in 2nd with 3.73's is a much different speed than with 2.73's. But ya, electronic transmissions definitely do have their positives.

Ya, I was just saying that they aren't computer controlled on the 4L60/700R4's.

Yep.......and I somehow missed the fact that you have a '93 with the 4L60/700R4 :o .

KW

I see. I got all the strange goodies found only in the 93's. I really don't see why they didn't just switch to the 4L60E from the start of the fourth gen. Same with MAF instead of speed density.