Gearing

One of the best features of the array of rear-drive Mitsus is their unusually large variety of transmissions and axle ratios.   This allows some flexibility in configuring a car for a particular purpose, such as towing, economy, accelaration, top speed, etc.  This chart shows all of the transmissions and final drive ratios and their combinative effective mechanical advantage.

For example, the first entry in the table shows first gear of the KM-110 transmission having a 3.525 : 1 ratio.  Moving over to the 3.31 axle column, we see the value 11.66, which is simply the product of 3.525 x 3.31. This figure represents the effective mechanical advantage of the combination of the transmission gear with the rear axle ratio.  The large the number, the easier the load and the higher the engine speed for a given road speed.

Obviously, tire diameter also affects overall gearing.  Integration of tire sizes is beyond the scope of this chart.  Instead, use the Revolutions Per Mile specification in the Tire Chart to find engine revolutions per mile for a particular transmission, axle and tire combination.  For example, 5th gear in a KM-119 with a 3.91 axle and 165/80/13 tires yields 3.334 x 886 =2954 engine Rev/Mile.
Transmission model and comments.
 Gear
 Ratio
 3.31 axle
 3.55 axle
 3.91 axle
 4.22 axle







KM-110  4-speed manual.
1
 3.525
 11.66
 12.5
 13.78
 14.88
    Span=3.525 2
 2.193
 7.254
 7.775
 8.573
 9.259
    Fits 4G32. 3
 1.442
 4.77
 5.113
 5.637
 6.088
    Not the same 4-speed as used in pickup with 4G52. 4
 1.000
 3.31
 3.55
 3.91
 4.22







KM-119  5-speed manual.
 1
 3.215
 10.63
 11.4
 12.57
 13.57
    Span=3.77
 2
 2.000
 6.615
 7.091
 7.818
 8.444
    Fits both the 4G32 and 4G52, though some clutch 3
 1.316
 4.353
 4.666
 5.144
 5.556
    parts must be swapped. 4
 1.000
 3.31
 3.55
 3.91
 4.22

5
 0.853
 2.821
 3.024
 3.334
 3.602







KM-130  4-speed manual.
 1
 3.74
 12.38
 13.26
 14.62
 15.78
     Span=3.74
 2
 2.136
 7.07
 7.57
 8.35
 9.01
     D-50 with 2.0 only. 3
 1.26
 4.17
 4.47
 4.93
 5.32
    
4
 1.00
 3.31
 3.55
 3.91
 4.22







KM-132  5-speed manual.
1
 3.369
 11.14
 11.94
 13.17
 14.22
     Span=3.936
 2
 2.035
 6.731
 7.215
 7.955
 8.592
     For 4G54.  I believe this fits the pickup as well.
 3
 1.36
 4.498
 4.822
 5.316
 5.742
     Will this fit the 2.4 or the 3.0 V6?
 4
 1.000
 3.31
 3.55
 3.91
 4.22

5
 0.856
 2.831
 3.035
 3.346
 3.614







MA-904A  Chrysler automatic, aka "Baby 904".
 1
 2.45
 8.104
 8.686
 9.577
 10.34
     Because of the slippage and torque multiplication
 2
 1.45
 4.796
 5.141
 5.668
 6.122
     behaviors of a torque converter, these specs are
 3
 1.00
 3.31
 3.55
 3.91
 4.22
     of limited value.






Comparison of the four differential ratios:

3.31
 3.55
 3.91
 4.22
3.31
1.073
 1.18
 1.27
3.55
 0.932
1.10
 1.19
3.91
 0.847
 0.908
1.08
4.22
 0.784
 0.841
 0.927

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