Toyota Repair: manual Rav4 speedometer failure, speedo gear, scantool

Question
My 1998 Rav4's manual transmission was recently replaced because it had started popping out of 5th and then 4th gear. Soon afterward I noticed that the speedometer and odometer were not working - they showed erratic but very low readings, getting progressively worse. The cruise control also does not work, unsurprisingly. The mechanic thought it must be the speed sensor in the new (used) transmission, and replaced this sensor with the one from my old transmission. The output now is slightly higher but still very low and erratic (at about 55 mph it reads 30, and flutters in what seems a random way). The tach is fine. I see from some other answers here that there may be a second sensor in the speedometer itself. Is this correct? Is it likely to be the problem?

Thank you!

Answer
Yes there is another sensor in the speedometer but it could be a problem with the speedo gear or pickup inside the transmission, the speed sensor signal should be checked according to the service manual, this can be confirmed by connecting a diagnostic scantool,if the sensor output pulse voltage is normal then the speedo should be replaced.