The 1950 Chevrolet pickup sounds like the 1962 Ford pickup I drove for my work decades ago. It was technically a 4 speed but first gear was “compound low”. I experimented with it a couple of times but top speed was about 10mph. Second gear was really first gear.
Back in the late 80’s/early 90’s quite a few small cars were available with either a 4 speed or a 5 speed manual transmission. VW, Toyota and the 90 Dodge Colt that I bought were available with those two transmission options on all (almost all in the case of Toyota) engine options. In every case that I checked out, and I did sample from each mfg, the 4 speed had a faster 0-60 time and got better city mileage and the same highway mileage. I chose the 4 speed.
@sgtrock21–You are exactly right that second gear was really first gear. The first gear was a “compound” or double low gear for heavy pulling. The gears should be labeled double low, low, second and high. High was direct drive.
The more complexity involved with an automatic transmission the more need there is for a home equity loan when it comes times to fix them… 
Reading keith’s post above reminds me of my '87 Ford Escort. It was available with an auto of some sort, and 4 speed and 5 speed manuals were offered. I got the 4 speed manual, and it was a HUGE mistake. It wasn’t bad on flat road, but here in Pittsburgh level ground is scarce, and the 4 speed had the ratios too widely spaced to accelerate uphill. Several long hills that I drove up regularly required me to buzz along at 3,500 RPM to maintain the 35 MPH speed limit. This wasn’t made any more pleasant by the fact that the 1.9 escort engine at 3,500 RPM sounded like a vacuum cleaner with an off-balance impeller. Upshift and it would immediately start to bog down. After 7 years, I traded it in for a Saturn, which had about the same engine torque:vehicle weight ratio, but it had a 5 speed stick. The difference on uphill grades was unbelievable! I could fly up hills in that Saturn without even trying.
I feel efforts like this will be the key to eliminating the need or any transmission.
Imagine, these motors acting as propulsion and brakes, all in one. Now, cost, the added unsprung weight and vulnerability to damage are big hold backs. But it’s getting there.
There’s more to gearboxes than the number of ratios, there’s also range of gearing or depth of gearing.
Here’s an example of a 6 speed with a narrow range of gearing, the Yamaha YZF-R1, a 1000 cc street legal track bike. It’s sold as a street bike mainly so it is legal as a production bike in World Superbike racing.
Here are the transmission ratios expressed as percentage of road speed at a constant engine rpm.
6th 100%
5th 93%
4th 83%
3rd 72%
2nd 62%
1st 50%
Even though it has six speeds, the depth of gearing is only 2:1, leaving you with not only a clutch burner of a first gear but a sixth that will have you looking for a non-existant 7th gear when you are cruising down the highway. Perfect gearing for a race track where 1st needs to be usable on the slowest turn and sixth for the longest straight part of the track, this narrow range of gearing makes all six gears usable on a race track but it makes for a gawd-awful street bike where you might want a nice low gear for stop and go gridlock and a decent overdrive for cruising the highway.
This also illustrates why a race bike or car is one of those “be careful what you wish for” things for the street.
Contrast this with the 5 speed transmission of a Kawasaki ZRX1200R.
5th 100%
4th 87%
3rd 70%
2nd 53%
1st 38%
depth of gearing 2.64:1
Heres a bike that has both a sensibly low first gear but also a 5th gear that’s not “pemanently in a passing gear” low. Even though it has only five gears, it has a wider spread of ratios than the R1 does.
Finally, the bike I own now is a Kawasaki Ninja 300 (EX300). It has a six speed gearbox.
6th 100%
5th 85.7%
4th 73.0%
3rd 60.8%
2nd 47.9%
1st 31.6%
depth of gearing 3.17:1
This is how six speed gearboxes should be done for a street bike. 6th is like an overdrive on the highway yet 1st lets you negotiate stop and slow gridlock without abusing the clutch. Uphill start on a 15% grade? No problem!
The real reason for these six or more speeds is to give automobiles the depth of gearing needed for good gas mileage without having ridiculous gaps between the gears. I’ll take five speeds with a 2.6:1 depth of gearing over a CVT with a 2:1 depth of gearing any day.
Just to muddy the waters, while there may be a theoretically infinite number of ratios between the upper and lower limits of a CVT, or an infinite number of numbers between 1 and 2, or an infinite number of positions you could occupy in a room, once you get beyond a certain point of measurement, and the discrete steps exceed your margin of error in measurement, going any further is meaningless. So there may be an infinity there, but we can’t perceive it, or it is of no value beyond a certain point to do so. .00000000000000001 isn’t different enough from .00000000000000002 to matter in reality for most purposes.
So let’s discuss Zeno’s paradox… for the transmission to change from one gear ratio to the next gear ratio first it must complete half of that journey. But to complete half of that it must first complete half of that half. But to do half of the half it must first do half of that…ultimately resulting in completing an infinite number of tasks, which is of course impossible. So shifting gears is impossible.
Sorry, couldn’t resist…
So let's discuss Zeno's paradox... for the transmission to change from one gear ratio to the next gear ratio first it must complete half of that journey. But to complete half of that it must first complete half of that half. But to do half of the half it must first do half of that...ultimately resulting in completing an infinite number of tasks, which is of course impossible. So shifting gears is impossible.
That’s not really a paradox so much as it is a logic fallacy. It doesn’t take into account that as the number of divisions approaches infinity, the time consumed for each division approaches zero.
Here’s an example of a paradox. “I always lie”
Regarding cvt trannys - while there’s theoretically infinite ratios available, we’re dealing with a digitally controlled device, so there’s a finite number of steps the controller will use.
There really is a point of diminishing returns when you make the steps smaller and smaller and very likely a point where the icreased friction of all the gears, unused but still meshed and freewheeling on their shafts, offsets any benefit from having more gear ratios.
The benefit of infinite number of steps in a gearbox is much like the benefit of continuous compounding of interest.
Let’s say you invest one dollar at 100% APR interest rate.
Compounded annually, you have $2 at the end of the year.
Compounded bi-annually, you have $2.25
Compounded monthly, you have $2.61
Compounded daily, you have $2.71456
Compounded hourly, you have $2.718127
Compounded continuously, you get $2.71828182845904523536028747135266249775724709369995… also known a Euler’s number or e, a mathematical constant used as the base of natural logarithms.
Even with infinite steps, there is an upper bound in vehicle efficiency.
The added gears are also being used to expand the range, not just fill in, that’s a big part of the mpg benefits that are causing makers to use these expensive, complex trannys.
They’re not just doing it for fun…
Added gears can expand the low range, the high range, or both. For example, the 4 speed transmission in my 1950 Chevrolet truck added a very low gearing. Fourth gear was direct drive as it was on a three speed transmission. On the other hand, the Borg-Warner overdrive added a set of gears after the transmission which not only provided an even higher gear in overdrive high, but provided a speed lower than direct drive but above 2nd gear called overdrive second. The four speed manual transmission in the Plymouth Volare and Dodge Aspen of the late 1970s provided a fourth gear that was an overdrive.
The shifts in the automatic transmission on my 2011 Sienna are practically imperceptible and it has at least 6 forward speeds. On the other hand, the GM Hydramatic of the 1940s through the 1950s let one feel every shift. I heard a rumor that Chevrolet and Buick developed a different automatic that depended on a torque convertor because these vehicles used an enclosed driveshaft (torque tube drive) that would accentuate the shifts that were already jerky. However, the Nash Ambassador had the torque tube drive and used the GM Hydramatic and I don’t think the shifting was any rougher than that of the Pontiac or Oldsmobile with the Hydramatic.
Have a question about transmission and CV axles.
When going 60mph and you brake, the rotors/CV axles slow down rapidly and stop…how does it slow down rapidly without breaking the transmission gears? Does the transmission “disconnect” from the CV axles when braking?
The same way the CV axles slow down rapidly and stop on a regular manual transmission when you brake from 60mph. The engine torque is not powerful enough to break the gears, especially when you figure that the throttle will be closed, the engine braking will actually help the brakes stop the car.
It stays engaged. (At least, on Jeeps they do). There’s a nice thump as the slack gets taken up, and then you start getting engine braking, even if you don’t want it.
The CVT still needs a torque converter or some othe way to disconnect from the engine at a stop.
Before we all sing praises of CVT, download the pdf in the following link
http://www.engineering108.com/pages/Automobile_Engineering/Continuously-Variable-Transmission-ebooks-free-download.html
CVTs are great in theory, but frictional and component deformation loses have yet to be mitigated. That’s why trucks have 18 speeds instead of CVTs.
Trucks have 18 speed transmissions mostly because they need a wide range of gear ratios, not closely spaced gear ratios. On a Eaton Fuller 18 speed, the highest ratio is 0.73 and the lowest ratio is 14.4.
A classic Borg Warner T10 4speed from the '60s muscle car era had a 1.00 4th and a 2.36 first.
Here’s gears 13 through 17 on the Eaton Fuller 18 speed.
1.62
1.38
1.17
1.00
0.86
Here’s gears 2 through 6 on a Kawasaki EX300 motorcycle.
1.789
1.409
1.160
1.00
0.857
You can see that the ratio spacing is quite comparable, it’s just that first on the motorcycle is a ratio of 2.714 while first on the truck is a walking speed with the engine redlined 14.4:1 ratio.
Also, truck drivers don’t always use every gear. If lightly loaded and not going up a hill, they might take off in 2H and go through the gears without splitting shifts.