I was taught that on slick roads you wanted to use a gear higher than you normally would, to reduce torque and thus the chance of a spin-out. Not much you can do about that with an Automatic transmission, though if the roads are extremely slippery and you aren’t going too far, I heard that it’s advisable to put the parking brake on a couple of clicks
Zor:
Yes. The car may decide not to shift down if you’re going too fast, though.
You can also shift up (1->2->D) at any time, without pressing the lock button or pulling the lever. I’ve found this useful in situations that closely resembled stop-light drag racing, but of course this only took place in designated legal areas. 
:eek:
I’d advise against that! Strongly.
You’ll wear out your parking brake drum (in case of rear disk brakes), or your entire rear breaking system (in case of rear brake drums).
YMMV is definitely the watchword when it comes to settings beyond D. On a Mercedes-Benz 5-speed automatic, there is no 1st gear setting, but putting the selector in 2 will tell the transmission to downshift to 1st gear as soon as the engine speed is low enough to do so. When accelerating, slapping the lever up to 3 will let the transmission shift into 2nd gear and you can then put the selector back into 2 to hold 2nd gear. Further upshifts will occur as the selector and engine speed permit. On most American passenger car automatic transmissions (I say most but every one of the dozens and dozens of cars I’ve driven behave this way), the selector sets the highest gear the transmission will use. When I got my 1984 Hurst/Olds, I assumed that the special shifter would allow me to choose what ever gear I wanted, when I wanted it. Not so; it merely acted as a more precise version of the typical automatic shifter (i.e. slap a different lever for each upshift/downshift). I currently have a Japanese car with an automatic transmission; it behaves just like any American car in that respect.
**The overdrive and lock-up on the torque converter are not silly nonsense. The TC lock-up helps improve not only fuel efficiency but also helps the transmission itself to operate cooler and more efficiently. The OD and TC lock-up also help engine life by allowing it (the engine) to operate at a lower RPM at cruising speed on flat highway driving conditions. BTW, many vehicles come with both OD and TC lock-up on the same transmission. And those aren’t only the cheap ones with 3 gears. Many of the high torque diesel engines, when not loaded down to full capacity require extra OD ratios to keep from over revving the engine at highway cruising speeds. TC lock-up helps in that situation.
A properly calibrated locking TC should not produce any hesitation in gear change when the vehicle needs to shift. The two shift schedules should be independent of eachother. And the TC lock-up is usually dependent on vehicle acceleration as well as speed and throttle position, so as soon as the vehicle comes to a hill, for example, the TC should unlock, allowing the TC to multiply engine torque giving the vehicle the required wheel torque to make it up the hill or past whatever other hindrance.
BTW. I bet the 4th gear on your Bonneville has an OD ratio. What you meant by four “real” gears is what I do not understand. Unless people consider OD gear ratios as imaginary. 
**
What size engine do you have? I’m not saying the transmission is not at fault, it may be calibrated poorly. But I’m just curious as to what engine is in your truck.
jeel
You’re right about everything you said. But I think I mentioned that what I was saying was for drivers like me. Unless gas hits $2 again before I get a pay raise, I don’t really care what it costs for gas. There’s no need for me to have SILLY (yes, in my case, SILLY) little devices to try try get get an extra 2MPG out of my fuel use. I can’t imagine that there aren’t a LOT of people who drive like I do.
As for the other points, I concede your point again, but trucks, cargo, lots of weight, etc., doesn’t apply to vehicles meant to be driven for pleasure as much as transportation.
Ah, the Ranger… it’s a tiny little 4 cylinder, and I don’t even know how small it is. I didn’t look when I bought it – all I cared about was getting the cheapest econobox I could for work (uh, despite this statement, I don’t mean for the price of gas). So, to a large degree, the engine has a lot to do with how un-fun it is to drive. But the transmission SLAMS when I nail it, and it’s still very, very noticeable shifting when I drive “normally.” When the vehicle is in overdrive and I step on the gas, it takes a considerably longer to disengage and engage in a low gear than the other gears, or my car. I’m assuming that this is because it’s not a “normal” 4-th gear, it’s an overdrive gear.
My statements about “real” fourth gear versus an overdrive gear reflects my admittedly ignorant knowledge that there are two different types of overdrive systems (plus lockup torque converters). Those that have a “real” fourth gear that is like any of the other gears, and those that drive in third with a supplemental gear somewhere between the driveshaft and the output shaft.
For the record, I am an engineer in one of the big three, but I don’t know anything about the design of transmissions. I DO know the types of transmissions I like to drive!