SM465 Steel Speedo Gear?

[wixthedog]

So I ran into something I can't Google my way out of and I need the experts help!

My speedometer never has worked so I did some tests and found that the issue was likely inside the transmission. I hooked a drill up to the cable and tested everything from the transmission up and the speedo acted accordingly.

I have since removed the transmission but noticed that the gear end spins when I turn the end shaft. I went ahead and removed the large adapter nut and found a 22t steel gear marked with an "M" instead of the colored plastic thing I was expecting.

Any insight on what this is?

Some pics for reference:

[AussieinNC]

The steel gear runs against the radial gear that is on the output shaft and can be seen now thru the hole where you removed the metal piece.

Try and push against the radial gear and see if it turns on the shaft...if it does, the retainer clip that locates it has broken.

If it does not spin on the shaft, replace the steel driven gear and turn the driveshaft...you will have to have the rear wheels off the ground and the trans in Neutral...make sure you chock the front wheels....

The inner shaft of the steel driven gear should turn when the driveshaft turns.....

These rarely give trouble...the biggest failure point in the system is either a broken drive cable or the square end of the drive cable has rounded off and cannot grip into the driven gear end piece.

Post a pic of the trans end of your speedo cable....showing the inner cable...

[wixthedog]

Thank you for the reply.

It appears I was confused between two different styles of speedometer gears and that did not match up with what reality was when I opened it up for inspection.

I initially tested the cable (at the final termination end) with a cordless drill and the speedometer worked as advertised. The transmission is out of the truck now for other refit type stuff but I have spun the output shaft and watched the end of the steel gear(where the speedo cable inserts into) turn without issue.

In the end, I believe you are spot on and that the end of the final drive cable has rounded and is just worn out. They are cheap and I'll grab another on the next parts run.

Below is a pic of what caused my own confusion. Everything I read before actually seeing led me to expect this when I opened it up with my own eyes.