Speedometer Calibration
      Variables such as the vehicle's axle ratio and tire diameter affect the accuracy of the speedometer. The following speedometer drive gears and driven gears are available for the 700R4 / 4L60 transmissions. Most cars and trucks with low rear end ratios will take a 15 tooth drive gear. There are two driven gear housings, one for 34 through 39 tooth driven gears and one for 40 through 45 tooth driven gears. Look at the bottom of the speedometer face for the numbers 940, 960, 1000, or 1020. These numbers are the number of revolutions the speedometer cable must turn in one mile of travel. Your speedometer may or may not show a number. Most speedometer from 1965 on use 1000.

.
A spring clip retains the speedometer drive gear on the transmission output shaft.

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.

To determine your rear end ratio, raise both tires off of the ground, turn both tires at the same time one complete turn, at the same time count the turns of the drive shaft, this is your ratio.

#54. 700R4 Speedometer gear housing for 40 to 45 tooth driven gear (aluminum not plastic) (also fits Olds TH350). Cost $62.00

#54. 700R4 Speedometer gear housing for 34 to 39 tooth driven gear (aluminum not plastic) (also fits Olds TH350). Cost $42.00

#54U. Good Used Speedometer gear housing for 40 to 45 tooth driven gear (aluminum not plastic). (OUT OF STOCK) Cost $23.00

#54U. Good Used Speedometer gear housing for 34 to 39 tooth driven gear (aluminum not plastic). Cost $12.00

#54P40. Speedometer gear housing for 40 to 45 tooth driven gear (plastic not aluminum) (also fits Olds TH350). Cost $29.00

#54P. Speedometer gear housing for 34 to 39 tooth driven gear (plastic not aluminum) (also fits Olds TH350). Cost $12.00

The above and below 700R4 parts also fit non-Chevy TH350 transmissions.

#54X. Speedometer drive gear, comes in 15, 17, 18 or 19 tooth. Cost $8.00

#54XX. Speedometer driven gear, comes in 34 to 45 tooth. Cost 11.00. (Also fits 208 transfer case.)

Speedometer Calculator, Click Here

  Retainer, Cost $5.00

  5/16" Clip, Cost $3.50

O-Ring, 700R4 housings come without this O-ring. Cost $1.50

Gear seal, new 700R4 aluminum housings come with this seal, used or plastic housings don't come with this seal. Cost $1.50

#208. This is a 15 tooth speedometer drive gear for a GM 208 transfer case. ( We know where to get more for $199.00 each, our cost ! ! !) New Old Stock. (OUT OF STOCK) Cost $59.00

#208D. This is a 13 tooth speedometer drive gear for a GM 208 transfer case. This is actually a Dodge 208 transfer case drive gear, but will work on a GM 208 transfer case if you make a .293" spacer from your old GM gear and use it as a shim on one end. Cost $32.00

#13. Chevy / GMC 13 tooth, 38 spline transfer case speedometer drive gear. Fits some 1988 up Chevy / GMC 241 transfer cases. Cost $19.00

GM / Dodge / Ford Ratio Adapter

#54RA. This GM / Dodge / Ford ratio adapter will slow your speedometer reading down. Made for low rear end ratios with short tires. Offset for clearance reasons. If your GM speedometer reads too fast with 15 and 45 teeth gears then you need this part. This part will slow down your speedometer reading. Cost $62.00

#54RA2. If your truck tires have been switched to larger tires or you just need to speed up your speedometer this one will correct your problem. This part will speed up your speedometer reading. Cost $62.00

Other ratios available on special order, allow 2 to 4 weeks. No refunds on special orders. The male side can be turned 180 degrees, just remove the 4 screws and turn. We can slow your speedometer down as much as 58% or speed it up as much as 200%. Cost $72.00

#54SPK. Ratio Adapter Small Part Kit. These parts come with the ratio adapter. Cost $9.00 Qty 12345

Ratio Adapter with 2 cables for GM and Dodge starting at $127.00.

Ford Ratio Adapter

#55RA. Ford speedometer ratio adapter. Must be used with screw on cable top and bottom. Comes in minus 15 or 23% and plus 44%. Cost $89.00

#54K. Universal speedometer cable, cut to fit. Fits TH350, TH400, 700R4, PG, 200, 200-4R, 904, 727, C4, C6 and AOD. 7/8 thread bottom, 5/8 thread top. Cost $69.00

  #54MG. Eight pulse signal generator for your electronic speedometer head. This goes behind your dash and plugs to the head and drives off of your old speedometer cable. Doesn't include the cables. Can be installed inline for both mechanical speedometer and pulse generator. Cost $63.00

#55X. Speed sensor for above 34 to 39 tooth driven gear. (Black) $69.00

#55XX. Speed sensor for above 40 to 45 tooth driven gear. (White) $56.00

These two sensors put out 4 pulses per turn. A four pulse sine-wave (A.C. current or alternating current) signal is required by the 1990-1993 TPI, 1992-1993 LT1 engines and 1990-1993 Camaro 3.1 / 3.4 V6 engines.

#55B. Speed sensor for above 35 to 45 tooth driven gears with speed sensor and speedometer drive. We must know what gear tooth count you're going to use with the sensor. This is needed for an EFI conversion. Cost $84.00