been researching but need help pls. 75 fj40 auto trans, stock transfer case no speedo cable. Running a cable is tricky w my headers so was thinking of digital. What sensor at the transfer case do I need that has the right fitting?
You need a hall effect magnetic pulse sender. I have one on my 69' FJ40 and it works the Auto Meter digital/programmable speedometer just great. I am running the stock 3 speed case also. Check out www.speedscenewiring.com and see what they have, that's where I got mine 12+ years ago.
The sensor I used was for a GM I believe and the threads were close but not perfect. They were a tad too loose on the Toyota case. I wrapped a ton of Teflon tape around the threads and it's been fine. You'll also need to find the right adapter pin to drive the sensor. Wiring from the sensor is only 2 wires.
Oh, and programmable means you'll never have to worry about the damn thing being accurate after changing tires or re-gearing. I've calibrated mine multiple times over the years and it's very simple. Put it in calibration mode, drive a known 2 mile distance and re-set it. You're done after that. Very accurate if done correctly.