I know our speedos are electric,but do they still use the replacable gear on the sending unit?????

 

When I pulled my trans for a clutch changeout, there was no wiring to a sending unit or transducer. If I recall correctly the speedometer signal comes from the antilock sensor and tonewheel on the rear axle.

 

Say what? Speed from a wheel sensor? That's new for American autos and something I gotta check out. Very interesting...
(and I'm not being snarky, this truly interests me. Thank God I have access to things like the FS manual and AllDataPro site)

 

I can't upload from my iPad and e image is inside a secure site, so...
The Vehicle Speed Output Sensor (for the speedo) for an 06 ram 2500/3500 auto with 2WD or 4WD is located in the overdrive extension housing of the tranny. It is a two pronged, round/oval shaped plug on the driver's side of the tranny and would be the most rearward on a 2WD truck. A 4WD has the t-case selector plug further back on the t-case.

The ABS tone rings at the wheels provide info to the ABS controller and share that with the PCM to know if e truck is stopped or the wheels are locking up. This info does not affect the speedo reading.

The sensor does not use a replaceable gear inside the tranny, or outside for that matter, that I'm able to see from the exploded view or parts list for that trans.

 

they have been running a tone ring in the rear axle for years. GM has been doing it as well for years.