My 2 pennies: Leave the OD on all the time. That is the way it is designed to work, and in my opinion it works very well. If I am just cruising around, the computer pops me into OD as soon as I shift from 1st to 2nd. If I am stuffing my foot into it, then the computer takes me out of OD for better acceleration.
No other manual tranny in the world can do this: You are cruising at around 2,000 rpm on the freeway in the fast lane. You come upon some slower traffic. You stab the gas pedal, the OD instantly disengages, your head snaps back, and you make your pass. Settle back into cruise mode and the OD re-engages itself. Your left foot never stopped tapping the floor in time to the music.
Here's another one for you: About two years ago, I came out of the movies with the wife, hopped in the vette, and the clutch wasn't disengaging well enough to shift the gears. (Slave cylinder developed a leak and fluid got too low in the master cylinder and sucked air.) I drove about twenty miles home in second gear, toggling the OD on and off. 2nd gear OD is about like third gear, so cruising the slow lane on the fwy wasn't even a big deal.
Anyway, I don't believe it is necessary to fiddle with the OD button unless you want to... and I am sure that it is unnecessary to use the clutch when turning the OD on and off. The OD unit is basically a 2-speed auto trans, it has its own auto clutch inside it. When you want to accelerate, just floor it... it will jump itself out of overdrive in less than a second, and then it won't go back into overdrive until you reach a steady 4th gear cruising speed. According to the owner's handbook, the OD on/off button is only there for use in special situations. The example they give is if you want extra engine braking in a long, steep downhill.
This is the perfect transmission for me. It combines the fun of a manual with the convenience of an automatic. The bad rap it has comes from two things: first, the early units were buggy and inconsistent. Lots of them were rebuilt under warranty which ****ed off GM, and then lots of them had to be rebuilt after the warrany expired, which ****ed off a lot of vette owners. Second, the fluid needs to be changed regularly or else the OD unit will croak. GM says it must be changed every 30,000 miles, but Gearzone says if you change it every 10,000 miles the OD unit will last forever. Note that for many owners, the first time they thought of changing the fluid was when it died somewhere between 50k and 100k miles.
One last thing: I am told that some vesions of the OD had a very deep overdrive gear ratio. This may explain some owner's habit of turning off the OD at startup, if shifting from 1st to 2nd(with OD) caused their engine to bog down. On mine, shifting from 1st to 2ndOD is very smooth and comfortable. My OD ratio puts me a bit over 2000 rpm at freeway speeds. I love freeway interchanges (cloverleafs) where I am coming out of the 3/4 circle in 2nd gear OD... mash on the gas to merge with traffic and that sucker jumps out of overdrive and takes off like a rocket.
As you can tell, I love the tranny. I wish the C5 had the same kind of thing. Even as nice as the C5 6-speed is, it still is just a 4-speed with two overdrives added on, just like my friend's 89 and my wife's 2001 Camaro SS. I have a 4-speed with an automatic overdrive added on, and that's a lot more fun.
Anyway red88conv, congrats on your new ride. Change that OD fluid and then schedule the next change for about 15,000 miles down the road and you should be fine. And try just leaving that button alone... you can always come out of OD by flooring it!
Dan
Mike
ad OOps sorry, not OT
