VEHICLE SPEED SENSOR INFORMATION
Computer Controlled engines and/or transmissions require a Vehicle Speed Sensor (VSS). Although there are a couple of different styles of sensors, they all perform the same type of purpose - to tell the computer (or PCM) how fast the vehicle is traveling. Using this data, the computer can determine how to adjust for freeway driving, fuel economy, transmission shift points (automatic only), and how to get the best performance at any given moment. Power and fuel economy will be lost if the VSS is not functioning properly. Different styles of VSS are shown below.
| Application | Signal type | Pulse count per driveshaft revolution |
Mechanical Speedo driven signal available | ||
| 1986-1992 GM TBI engines 1985-1989 GM TPI engines | Square wave signal - two wire sensor “Pulse Generation” | 2 | Yes | ||
| GM trucks (1993-current) | Sine wave signal - two wire sensor “Voltage Generation” | 40 | No See voltage generation chart |
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| Jeep (1987-current) | Square wave signal - three wire sensor “Pulse Generation” | 3 | Yes |
As can be seen above, some Vehicle Speed Sensor signals can be created from a standard mechanically driven speedometer. These drivetrains are much easier for swapping because it allows the use of almost any transmission or transfer case combination.
For the 40 pulse GM VSS, there are much fewer options. Please refer to the flowchart below to determine the correct location for the GM 40 pulse VSS in your application.
We do not offer any type of mechanical speedometer driven VSS units; however, these types of units (pulse generation / square wave) are available from most companies that supply engine wiring harnesses or custom speedometer shops such as Nevada Speedometer, Tel# (775) 358-7422.
LATE MODEL GM ENGINE VOLTAGE GENERATION
GM 40 pulse Vehicle Speed Sensor - Proper Location Options Below:
1. Computer Controlled GM engine with a computer controlled automatic transmission. Transmission Output VSS
Transmission:
700R/4L60 - See the adapters listed under 700R/4L60 in your specific vehicle year.
Early 4L60E - All vehicles can use Part No. 716073. For Jeeps and Toyota Land Cruisers, you can also use the adapters listed under the 700R/4L60.
Late 4L60E - See the adapters listed under 4L60E in your specific vehicle year. 50-0405 or 50-0405E
4L80E - Most early transmissions have a internal tone ring for VSS. The 1997 & later 4WD transmission did not. If you are using a 1997 & later transmission, you need to install a tone ring. On later model transmissions coupled to an Atlas, we offer kit 50-6409 which will provide a rear reluctor ring.
2. Computer Controlled GM engine with non computer controlled automatic or manual transmission. VSS is needed, but location is not critical
The VSS can be in the transmission or transfer case and still function properly. We offer a reluctor kit that fits on all of our tailhousing kits for the Jeeps. This kit is an external mounted unit that provides a Tru 40 Pulse required for the computer system. The reluctor ring gets mounted to the transfer case yoke. The kit is offered in several yoke styles except a flange yoke. Our Tru-Pulse kit fits the Dana 20, 300, NP, and Atlas transfer cases with 32 spline outputs.
50-5040 is a 1310 non C.V.
50-5041 is a 1310 C.V.
50-5042 is a 1350 non C.V.
50-5043 is a 1410 non C.V.
3. Computer Controlled GM engine & drivetrain in a GM 4WD vehicle (Atlas T/C install) Transfer case tailhousing VSS
Atlas transfer case Kit AVT-T or AVT-G2 provide a VSS tailhousing with the provision for a low-range switch. If the Atlas T/C is not being used, then a GM transfer case that came behind the donor engine can be used. All other transfer cases will require a custom fabricated VSS.
P/N 716073