GM 700R4 / 4L60 Speedometer Gear Info

 

Drive Gear
Tooth Color GM Part #  
15 Gray 8642620  
17 Red 8640517  
18 Blue 8640518  
19 Yellow 8640519  
       
Driven Gear
Tooth Color GM Part # (Electric) GM Part # (Cable)
34 Light Green 9774413 25513041
35 Orange 9780387 25513042
36 White 1359270 25513043
37 Red 1359271 25513044
38 Blue 1359272 25513045
39 Brown 1359273 25513046
40 Black 1362048 25513047
41 Yellow 1362195 25513048
42 Green 1362049 25513049
43 Purple 1362196 25513050
44 Dark Grey 9780470 25513051
45 Light Blue 9775187 25513052

 

With 15 Tooth Drive Gear

Axle Ratio

Tire Height

Driven Gear Teeth

4.56

33

42

4.56

35

39

4.10

26

45 will work, but will read about 3 MPH fast at 50 MPH.

4.10

27

45

4.10

28

44

4.10

29

43

4.10

30

41

4.10

31

40

4.10

33

38

4.10

35

35

3.73

26

43

3.73

27

42

3.73

27 1/2

41

3.73

28

40

3.73

29

39

3.73

30

38

3.73

31

36

With 17 Tooth Drive Gear

Axle Ratio

Tire Height

Driven Gear Teeth

3.73

28

45

3.73

29

44

3.42

26

45

3.42

26 1/2

44

3.42

27

43

3.42

28

42

With 18 Tooth Drive Gear

Axle Ratio

Tire Height

Driven Gear Teeth

3.23

26

45

3.23

26 1/2

44

3.23

27

43

3.23

28

42

 

                          

                                              

 

 

 

 

 

 

 

To determine your tires true diameter in relation to determining what speedometer gears you need, measure from the ground up to the center of the axle then multiply by two. The actual run out of the tire can be as much as 2 to 3 inches less than what the circumference of the tire measures. In effect your tire has two diameters.

Twelve speedometer driven gears are available for the 700R4 / 4L60 transmissions to calibrate the speedometer with various axle ratios and tire diameters. The number on the driven gear housing must match the number of teeth on the driven gear. Unless driven gears with more than 45 teeth and / or drive gears with fewer than 15 teeth become available, it will be impossible without using a ratio adapter to have an accurate speedometer with rear end gear ratios lower (higher numerically) than 4.10:1, unless 27 inch or larger tires are installed.

                                           

 

Speedometer Drive Gear Installation Instructions: Word Format or Text Format

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