I’ve had my car for three years and I just realized yesterday that I have a little button on the side of my automatic shifter. I noticed when I pushed the button, my dash had a light that came on saying “manual”. What is this for? Is this for putting the car in overdrive? I googled, but kept getting hits for converting an automatic to a manual. It is a Ford Probe if that helps.
From what I can tell, it prevents automatic shifting, so you have to do it. You RTFM?
My WAG: Your average T-bar auto has 1,2 (and sometimes 3) settings below D. You can use these to hold lower gears for longer than the automatic box would otherwise, and then shift up manually. This isn’t the same as a true manual though, because you can’t hold higher gears. If you select 3, and your speed becomes too low, the car wil override your decision, and you’ll find yourself in 2nd.
Now, it sounds like you’ve got some sort of set-up where you can hold gears in both directions (upshifting and downshifting), which makes your car pretty much capable of being a genuine clutchless manual. This tech isn’t new - I remember an Australian-built Ford muscle car of the early 70s had it. It’s never really taken off though.
Of course, I could be completely talking nonsense, but that’s my guess.
You know that owner’s manual that came in the glove box when you bought the car?..
I’ll bet the answer to your question is in there.
My car has a similar switch. The owner’s manual says the “Manual” selection is for “performance” driving. I think it’s still a torque converter automatic, though.
I believe BMW’s going to offer a transmission in some 2004 models that will be a clutch-pedalless manual, where you shift, but the car handles disengaging/engaging the clutch.
What’s happening to our automatics? sigh I swear to God, if I can’t get a manuel clutch in a few years, I’ll be pissed.
automatics= manuels
Thank you for the replies. I did some more asking, and ran into a gearhead friend who guessed pretty much the same thing suggested by TheLoadedDog. I believe you that the technology isn’t new, my car is over ten years old, so though not dating to the seventies, it’s not exactly loaded with state of the art extras either. 
As to the obvious suggestion of looking in the owner’s manual, that would have been my first choice, had my used car purchase included one.
I like the sound of performance driving Ringo. I have tomorrow off, so I guess I’ll give it a try. I’m not all that great with cars, but when presented with the choice of regular driving and performance driving, I figure it’s worth a go.
As to the issue of not having a manual, give the manufacturer a call, or stop by your local dealer for that make. The former will probably offer you a free replacement book, and if not, the latter will be happy to sell you one for $10 or so.
This is the way most of these transmissions work: If you have the button you will also have an “overdrive” type transmission, i.e., with an additional gear (usually with a 1:1 ratio with the drive shaft) intended to improve fuel economy when driving at highway speeds. By default, overdrive “mode” is engaged when you start your engine. However, if you get into hilly terrain, it is recommended to disengage overdrive mode in order to keep the engine from “lugging” or downshifting unnecessarily. This is specially important if you are also using cruise control in hilly terrain. Pressing the button DISENGAGES the overdrive gear and an instrument panel light turns on to remind you of this fact. On my car (Jeep Grand Cherokee) the light reads “O/D Off” which I think is a bit clearer than “Manual” but that was your manufacturer’s choice I suppose. As others suggested, the Owner’s Manual should make all clear.
Ha! Renault has this on their Dauphine model in the late 50s, early 60’s. I believe they called it a Ferlac clutch. Start to move the shift lever and the system disengaged the clutch. Select the desired gear and release the lever. Clutch re-engages.