You will notice, if you look closely, the difference between some of the clutch splines and also the identification markings on the drive teeth in these seven stock factory gear ratio input shafts.
Doug Nash had a similar arrangement as the Pro shift. These pieces could be interchanged. Another company named G.E.R. also made gears for the A-833. They had a similar setup, except that it had 10 lugs instead of 12. It also required the use of G.E.R. hubs, whereas Liberty’s and Doug Nash used a stock configuration hub. ■
Again, close inspection reveals identification grooves that are machined in the barrel area of the gear. This allowed quick identification between the seven different assembly line ration cluster gears.
CHAPTER 2
FUNCTION OF THE A-833
The A-833 4-speed, like practically all muscle car–era 4-speed transmissions, is what is known as a constant mesh transmission. This simply means that all forward gears are in constant contact with the cluster gear in the case at all times. Even in reverse, the forward gears are in mesh, but since none of them are locked to the mainshaft while the unit is in reverse, the direction of gear travel can be reversed without damage.
Let’s begin by reviewing terminology. There are several terms that are used regarding the components of the A-833 transmission, as described in the image here.
A synchronizer is made up of several components. In addition, there were three different main designs as described in Chapter 1.
“A” is the synchronizer clutch gear. This is also known as a synchronizer hub. This is the part that attaches to the mainshaft via splines and is retained by a snap ring. The splines around the outer circumference match the splines on the inside of component B.“B” is the clutch sleeve. This is also known as a synchronizer slider. This, too, is splined on the inside, which mates with the outer splines of component A.“C” shows the three strut keys. These are sometimes called “dogs” or “shift struts.” They are retained in a slot in component A and held in by component B.“D” shows two strut key springs. These provide outward pressure to stabilize and retain the components in C.“E” is a synchronizer stop ring. Sometimes called synchronizer rings, these are sandwiched between the synchronizer assembly and the gear cone.
General operation of a synchronizer during a gear change starts at the shifter handle. Movement of the handle transfers to the synchronizer via rods, levers, shafts, shift forks, sliders, strut keys, and synchronizer stop ring to the appropriate gear.
While first through fourth gears are fully synchronized in the A-833, reverse is not. This makes it necessary to be fully stopped before attempting to engage reverse. Otherwise, a “grind” will occur. This is not the case with putting the vehicle into first gear; you can be rolling forward slowly and put it in first gear and it typically will not grind. This is because the 1-2 synchronizer is engaged when the shift fork moves the clutch sleeve.
During a shift, the shift fork moves the slider. The slider is splined to the inner hub. Keep in mind that the inner hub is splined to the mainshaft. Therefore, the synchronizer assemblies always spin at mainshaft speed. Continuing on, the slider moves the three spring-loaded strut keys, which move the brass synchronizer stop ring onto the gear cone. As pressure is applied to the stop ring via the strut keys, the ring matches the speed of the gear to the speed of the mainshaft. This entire action is a “synchronized shift” and happens as quickly as you move your hand.
Power Flow and Layout
1 This is the power flow of the A-833 in neutral. All gears are in constant mesh. However, because the 1-2 and 3-4 synchronizer sliders are in the neutral position, no power is going through the output shaft. Power comes in through the input shaft and runs the entire geartrain at engine speed.
2 In first gear, power enters the geartrain through the input shaft and travels down through the cluster gear. It is then transferred up through first gear. The power is transmitted through the 1-2 synchronizer assembly by moving the slider to the first gear position. This locks first gear to the output shaft. (The red arrow shows the direction the slider is moved, and the blue arrows show the direction of power flow.)
3 In second gear, the power enters through the input shaft and is transferred down through the cluster gear. It is then transmitted up through second gear. Again, this power is transmitted through the 1-2 synchronizer assembly by moving the slider to the second gear position. This locks second gear to the output shaft. (The red arrow shows the direction the slider is moved, and the blue arrows show the direction of power flow.)
4 Third gear power comes in through the input shaft and travels down through the cluster gear. It is then transmitted up through third gear. This time, the power is transferred through the 3-4 synchronizer assembly by moving the slider toward third gear. This locks third gear to the output shaft. (The red arrow shows the direction the slider is moved, and the blue arrows show the direction of power flow.)
5 In fourth gear, power comes in through the input shaft. The cluster gear is not in use at this time and just spins along. The power goes through the 3-4 synchronizer assembly by moving the slider onto fourth gear, effectively running power straight through the upper geartrain and output shaft. (The red arrow shows the direction the slider is moved, and the blue arrow shows the direction of power flow.)
6 Reverse gear is a different arrangement than most other manual transmissions of this era. To reverse, the lower reverse idler gear moves back and meshes with the teeth present on the circumference of the 1-2 slider and the reverse teeth on the cluster gear. This idler gear rides on an idler shaft and is not in mesh, except when in reverse. (The red arrow shows the direction the idler is moved, and the blue arrows show the direction of power flow.)
As stated earlier, first through fourth gears are fully synchronized. However, reverse gear is not synchronized and relies on the geartrain not being in motion to cleanly engage without grinding. The reverse gear arrangement is unlike any other passenger-car transmission of the muscle car era. It relies on a row of spur teeth in the outside circumference of the 1-2 slider. In the neutral position, this is splined to the mainshaft and is not engaged with any other gears. When the operator moves the shifter into reverse, this moves the reverse gear selector arm and this, in turn, engages the reverse idler gear between the teeth on the cluster gear and the teeth on the 1-2 slider. By doing this, it reverses the direction of the mainshaft, making the vehicle back up. This is a good compact design because most other transmissions of this era dragged the reverse idler assemblies along at speed all the time, which required using rollers and thrust washers. Consequently, it makes rebuilding this part of the
