Kenworth W900 N14 Celect, tack not working

I’ll probably get this wrong, but I think the tach reads off the bell housing.

Remove and clean debris off magnet, or replace. Screw in till it touches, then back off 1 and a half turns then lock jamb nut.

I think the cam/crank sensors deal with the ECM and start/no start.

@Goodysnap ?

 

Add - I think you can run a multimeter across the terminals to measure resistance (can’t remember the value) - to check the sensor is ok.

I think I just changed mine out.

I believe the sensor on the tail shaft of the tranny is to the speedometer. Or I have these the wrong way round.

 

The sensor on the back of the transmission is for the speedometer. If you have a sensor in the bell housing you'll see it with the wires coming out of it.

If not then it runs off of one of your engine sensors.

 

Depends - but it’s fairly obvious - the sensor with a couple of wires attached. Mine was bottom center.

 

I need some help with this the tach has never worked on myb94 kenworth w900 12.7 but my speedometer does my sensor on the tail of my transmission is a4 wire speedo sensor I don't have a bell housing sensor where can I start to look for the problem I switched out the tach with a extra 1 I have laying around that work and it still doesn't work any help would be much appreciated