KM164: Difference between revisions
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The '''KM164''' is | The '''KM164''' is a 5-speed manual transaxle primarily known for its application in the [[First Generation Magna#TM|TM Magna]] (produced between 1985 and 1987). While it functioned as a standard 5-speed gearbox for the driver, its internal engineering was a unique departure from traditional transmission design. | ||
The KM164 | The KM164 was a derivative of Mitsubishi’s earlier "Super Shift" or "Twin Stick" technology. While those older transmissions gave the driver a separate lever to choose between Power and Economy ranges across all gears, the KM164 automated this process specifically for the final gear. | ||
Mechanically, the main gearbox is a 4-speed unit but instead of a traditional 5th gear synchronization on the main shaft, the KM164 utilizes a vacuum-actuated servo. When the driver moves the gear lever into the 5th gear position, a switch triggers the vacuum servo. This servo shifts a separate "high/low" gear set on the input shaft. The transmission remains physically in the 4th gear gate, but the input ratio is increased to a higher "overdrive" ratio. To the driver, this feels like a standard shift into 5th, but internally, the entire input speed to the gearbox has been altered. | |||
This design allowed Mitsubishi to provide a 5-speed experience using a modified 4-speed architecture, saving on the cost of a total redesign during the TM Magna's development. However, the reliance on vacuum lines and servos introduced specific points of failure: | |||
*'''Vacuum Leaks:''' If a vacuum hose perished or the servo diaphragm failed, the car would often lose the ability to engage 5th gear entirely. | |||
*'''Shift Lag:''' Because the shift relied on engine vacuum rather than a direct mechanical link, the engagement of 5th gear could sometimes feel slightly delayed compared to the crisp mechanical engagement of gears 1 through 4. | |||
As Mitsubishi refined the Magna platform for the [[TN]] (1987) series, the KM164 was phased out and superseded by the [[KM210]] transaxle. | |||
==Technical data== | ==Technical data== | ||
{|cellpadding="3" align="left" | {|cellpadding="3" align="left" | ||
Revision as of 00:16, 4 January 2026
The KM164 is a 5-speed manual transaxle primarily known for its application in the TM Magna (produced between 1985 and 1987). While it functioned as a standard 5-speed gearbox for the driver, its internal engineering was a unique departure from traditional transmission design.
The KM164 was a derivative of Mitsubishi’s earlier "Super Shift" or "Twin Stick" technology. While those older transmissions gave the driver a separate lever to choose between Power and Economy ranges across all gears, the KM164 automated this process specifically for the final gear.
Mechanically, the main gearbox is a 4-speed unit but instead of a traditional 5th gear synchronization on the main shaft, the KM164 utilizes a vacuum-actuated servo. When the driver moves the gear lever into the 5th gear position, a switch triggers the vacuum servo. This servo shifts a separate "high/low" gear set on the input shaft. The transmission remains physically in the 4th gear gate, but the input ratio is increased to a higher "overdrive" ratio. To the driver, this feels like a standard shift into 5th, but internally, the entire input speed to the gearbox has been altered.
This design allowed Mitsubishi to provide a 5-speed experience using a modified 4-speed architecture, saving on the cost of a total redesign during the TM Magna's development. However, the reliance on vacuum lines and servos introduced specific points of failure:
- Vacuum Leaks: If a vacuum hose perished or the servo diaphragm failed, the car would often lose the ability to engage 5th gear entirely.
- Shift Lag: Because the shift relied on engine vacuum rather than a direct mechanical link, the engagement of 5th gear could sometimes feel slightly delayed compared to the crisp mechanical engagement of gears 1 through 4.
As Mitsubishi refined the Magna platform for the TN (1987) series, the KM164 was phased out and superseded by the KM210 transaxle.
Technical data
| Lubricant | 75W/85W Hypoid Gear Oil | |
| Capacity | 2.3 Litres | |
| Clutch Plate Diameter | 215 mm | |
| Clutch Operation | Hydraulic | |
| GEAR RATIOS | ||
| Final Drive | 3.187 | |
| 1st | 4.070 | |
| 2nd | 2.244 | |
| 3rd | 1.467 | |
| 4th | 1.105 | |
| 5th | 0.855 | |
| Reverse | 4.109 |
