Title says it all.
I always imagined that an automatic shift lever on the column could use a simple cable since it only moves in one direction (is this assumption true?)
However, a manual shift lever moves in multiple directions, and I can’t imagine the Rube Goldberg setup that one would need to hook it to the transmission. Anything made of levers and cranks and such seems like it would break after a few years.
Enlighten me.
All the (limited) ones that I know about use two cables. Let’s label them cables A and B. 1st gear will be cable A pulled. 2nd gear will be cable A pushed. 5th and reverse will be B pulled and pushed, respectively. 3rd and 4th will be both A&B pulled and A&B pushed, respectively. All of the logic for actually shifting gears based on those simple inputs happens in the transaxle itself.
Most of my knowledge is limited to hondas, so I’m not sure if other makers do things the same way. I will say that honda figured out how to get 6 speeds + reverse working with 2 cables, but I haven’t taken a close look to figure out how they did that.
Column shifts IIRC use a tube.
In the center is the steering shaft, solid and a direct connection to the steering box. None of this sissy collapsible safety stuff for a he man car. Around the out side of the steering shaft is a tube. At the top end is the shift lever, near the bottom is an arm that sticks out. When you move the shift lever up and down (1-2 or 3-4) the arm rotates around the steering shaft. When you move the shift lever forward or backward (2-3 3-2) the arm moves closer or further from the steering box.
A series of rods connect the arm on the shaft to the transmission
(Not really on topic, but …)
Shift lever mounted on transmission = four on the floor
Shift lever mounted on steering colum = three in the tree
Generally true of American cars in the 60’s. Unfortunately, there’s no cute rhyme for 4-speed column shifts, 5-speed floor shifts, etc.
I learned all about them from this site. It’s gotten a little ‘ad-infested’ recently, but it has diagrams!
The short answer is “not very well”.
The one I fixed 4-5 times was on a 1970 Ford Maverick.
It used a tube concentric with, and inside the steering column. The tube moved radially with the lever, and slid axially when the lever was pulled or pushed in the axial direction. The tube engaged one of two bell cranks (levers) at the lower/front end of the column, then to two push rods, Then to two more bell cranks on the exterior of the gearbox, which in turn drove the shift forks via slotted bell cranks internal to the gearbox.
There were nylon bushings at each end of the tubes, and each push rod joint as well. These tended to wear and get sloppy, resulting in binding and difficult shifting.
The real problem, though, was the escutcheon where the shift lever attached. The length of the lever provided far too large a couple for the cross section of the casting. Every single time a new (to that car) driver drove it, they would try to muscle, rather than finesse, the gearbox, and break that casting.
My dad always used to say “four on the floor and a fifth under the seat.” I didn’t know what he meant until I was almost finished with high school. I thought there was some turbo gear, that you activated with a button under the seat or something. :smack:
Excellent! These descriptions combined with the Howstuffworks link clarified everything. I found the detailed pages of the article to be quite interesting, since every article I have ever read about manual transmissions gives good diagrams of the gears and syncros and stuff, but never mentions the linkages of the shifter lever.
Just as I thought – a Rube Goldberg machine.
Anything that has bell cranks going to push rods going back to other bell cranks is asking for trouble.
[hijack]The one single time I held the power of a 30,000 hp engine in my hands was due to such a hokey arrangement. In older Naval power plants, there was a complicated linkage using rods and bevel gears to connect the throttle handwheels to the cams operating the high pressure turbine’s poppet valves. This linkage often had several joints in it and ran dozens of feet.
One time it jammed and the main engine watch (me) had to go to a gigantic globe valve upstream of the turbines and control the engines from there while they sorted out the throttle linkage problems. That was sweet, even if all I could do was make the thing go slower.[/hijack]