My regular odometer and trip odometer on my 87 305 TPI stopped rolling about a month ago, and I can't figure out why. Any ideas?

My Dodge van trip meter stopped working.I took it apart and found that a couple of teeth on a gear had broken off.I found one on ebay with close to the correct miles and replaced it.

If the speedo is right i would say that the above post is correct..... however if the speedo does not work then it probably is the spedometer clip in the transmission if the car is an auto.... happened to me in my last car with a 4L60...... tiny clip in the bottom of the pan