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Custom Calibrated DRAC Module VSSB Module TBI Gas & Diesel
Custom Calibrated DRAC Module VSSB Module TBI Gas & Diesel

Custom Calibrated DRAC Module VSSB Module TBI Gas & Diesel

Your Price: $125.00
In Stock.
Part ID:cc
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Choose Options

Module Type
89-91 DRAC
92-93 DRAC
94-Up VSSB
Core Charge
Current Module Label Details help
Vehicle Identification
Calibration Details help
The speedometer calibration comes from physically reprogramming the DRAC or VSSB Module to replace in your vehicle. Whenever you change to a different (taller or shorter) tire or gear ratio on your truck the speedometer will be off. We can calibrate the speedometer back to the calibration that the factory sets on the these speedometers and more. Any possible gear and tire combination is supported with great granularity.

This module is calibrated based on gear ratio and tire size. This calibration will get you a factory quality calibration with GM type gear ratios as well as aftermarket gear ratio combinations. Got a Ford rear differential gear in your GM with a different ratio than commonly available? No Problem! We can calibrate for any gear ratio or tire size.

Please provide the details for the product's ordering options to the best of your abilities. We need to know your gear ratio and tire size and the type of DRAC module your vehicle or configuration needs. We determine DRAC type best by it's part number and broadcast code. We can also determine the type by the application (Year, Model, Series, Engine).

Why would you want to calibrate your speedometer?

  • Have an accurate measurement of vehicle speed.
  • Resolve a lagging speedometer.
  • Measure actual mileage onto vehicle
  • Calculate fuel mileage from odometer or trip-odometer.
  • Correct ABS (Anti-Lock Brake System) operation.
  • Correct cruise control operation.
  • Transmission shift timing and quality characteristics.
  • The DRAC/VSSB Module affects all these and more!




How To Order (help)

UD Module re-manufactures the various DRAC/VSSB modules and then creates the exact calibrated module you need for replacement. For custom calibrated modules where a differential gear ratio or tire size has changed we need the current Gear Ratio and Tire Size. To match the correct module for replacement we need you to remove your original module and record the Broadcast code (typically 3-big-characters) and/or the GM Part Number (under the 3-character code) and we build you a correct matching replacement module. Read below for more details on information needed

Module Type

Select the module type that best matches the year model of the vehicle the replacement module is going into. We will compare this selection to the additional information provided such as the vehicle details and the broadcast and part number and provide what is correct. There are years that different type units were used and we are aware of those crossover years and know what is compatible, don't worry too much about this selection being an issue, leave that to us.

Gear Ratio

To find your vehicle's Rear End (differential) gear ratio, the RPO codes list in your glove box is the easiest way. This is the sticker inside the box with a lot of 3-character codes. Find the gear code, this is typically GU4 (3.08) GU6 (3.42) GT4 (3.73) and GT5 (4.10) being the most common. Another method, you can call a GM Dealer's service department and provide them with the last-eight digits of your VIN and they can tell you the factory build gear ratio.

Tire Size

Check the current tire size on the vehicle. The absolutely preferred tire size measurement will be to use the P-Metric size on the sidewall. For example: 245/75 R16, please do not provide an estimated tire size diameter when a P-Metric or true size (like 33x12.5 R15) is available as this greatly affects accuracy of calibration.

Broadcast Code and Part Number

First, the module will likely need to be removed from the vehicle to retrieve the information. You'll need the broadcast code and the GM part number off the old module for the order form above.

Broadcast Code - In Purple

Part Number - In Green