Speedometer Gear Calculator

Speedometer Gear & Tire Calculator

Speedometer Gear Charts

GM – 200-4R

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Drive Gears	Driven Gears
10 – green	26 – brown
11 – orange	27 – black
12 – red	28 – yellow
13 – white	29 – green
—	30 – blue
—	31 – white

Notes: 1" steel housing. Drive gear in governor — separate replaceable inside oil pan.

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GM – TH350

Drive Gears	Driven Gears
7 – pink	18 – brown
8 – black	19 – natural
9 – green	20 – blue
10 – red/purple	21 – red
17 – red	22 – gray
18 – blue	34 – light green
19 – yellow	35 – orange/pink
20 – brown	36 – white
—	37 – red
—	38 – blue
—	39 – brown
—	40 – black
—	41 – yellow
—	42 – green
—	43 – purple
—	44 – dark gray
—	45 – light blue

Notes: Chevy = 1" housing; BOP = 2.078" housing for 34+ tooth.

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GM – TH400

Drive Gears	Driven Gears
7 – red	16 – (truck)
8 – black	17 – (truck)
15 – brown/gray	18 – (code H)
16 – orange	19 – (code J)
17 – red	20 – (code K)
18 – yellow/blue	21 – (code L)
19 – yellow/white	22 – (code M)
20 – green	34 – light green
21 – black	35 – pink
—	36 – white
—	37 – red
—	38 – blue
—	39 – brown
—	40 – black
—	41 – yellow
—	42 – green
—	43 – purple
—	44 – dark gray
—	45 – light blue

Notes: Uses housing appropriate for 34+ tooth gears (case mounted forward of tailhousing).

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GM – 700R4 / 4L60 (Speedometer Gears)

Drive Gears	Driven Gears
15 – gray	18 – brown (truck)
17 – red	19 – dark aqua (truck)
18 – blue	20 – silver (truck)
19 – yellow	21 – red/chartreuse (truck)
20 – brown	22 – gold (truck)
—	23 – maroon
—	24 – dark blue
—	34 – light green
—	35 – orange/pink
—	36 – white
—	37 – red
—	38 – blue
—	39 – brown
—	40 – black
—	41 – yellow
—	42 – green
—	43 – purple
—	44 – dark gray
—	45 – light blue

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Chrysler – Torqueflite (A727 / A904)

Driven Gear Teeth
25 – light green
26 – red
27 – beige
28 – light blue
29 – black
30 – yellow
31 – green
33 – yellow
34 – green
35 – orange
36 – red
39 – green
40 – orange
41 – red
45 – yellow

Notes: Uses 1.75" driven-gear housings. Tailhousing-mounted on 2WD applications; housing orientation varies depending on tooth count range (25–31, 32–38, 39–45).

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Ford – C3 / C4 / C6 / AOD / Other

Drive Gears	Driven Gears
6 – machined (C6 only)	16 – tan
7 – machined	19 – tan
8 – machined	20 – orange
9 – machined	21 – red
23 – white (retrofit)	—

Notes: Drive gears are machined into output shaft. The 23-tooth gear is a retrofit for 3.73–4.10 axle ratios — limited service life.