Can I bypass my transmission speed sensor and install a different type?

Question

I'm working on a 1998 Nissan Frontier XE King cab automatic transmission 2 wd

The vehicle speed sensor (vss) is located on the side of the transmission near the back. It has a two prong electrical connector. The old one was really difficult to get out. It ended up breaking off but I was still able to get the rest out.

I noticed some fluid leaking out that the Haynes manual didn't mention. Just a few drops. After removing the old vss I found a broken plastic gear on the end. I assume the rest of the gear is in my transmission and this is why the vss failed. I'm not sure how to get the broken plastic peice out, or if it even really matters because I'm pretty sure it's been like that since I had it.

The new speed sensor I bought is not the same sensor and doesn't include the plastic gear on the end, even though it's listed on multiple auto parts stores as a fit for my vehicle. Only one on Amazon had a plastic gear on the end and looked similar to mine so I'm hoping it works.

But if it doesn't, is it possible to install a wheel tachometer and connect it to the same two prong connector and send speed data that way? Or some other device that can plug into the same connector that sends accurate data?

Answer 1

Many devices will capture signals, but you need to know what type of signal to send and also how many pulses per revolution. Otherwise it won’t work.

Based on comnent:

I fitted a rev counter from a petrol car into a car with a diesel engine by changing the instrument assembly.

So rev counter was driven off the coil so needs 2 sparks per engine revolution to indicate correctly. Fitted 1 magnet to the engine crank pulley and a hall effect sensor with a triggering circuit - worked fine. Can’t remember the details now as it was more than 20 years ago...