Is it worth getting speed sensor inside transmission repaired? on 2002 Toyota RAV4

Manual trans, 85000 km (60000 mi), prob with speedometer since March 2010, still not fixed: speed sensor outside the transmission was changed but now it looks like they have a gear to change inside the trans, $2400 to fix.I'm wondering if that is the beginning of more problems. Spent $5300 in last 3 years (bearings, brakes, suspension coil, etc).

Asked by for the 2002 Toyota RAV4
are they positive that will fix the problem? it calls for 5 hours to pull the transmission. i'm not sure how much extra time to change the sensor. the speedometer gear in the transmission is about $40 and the speed sensor in the transmission is about $245...
Hi Goodguysdiesel, I've asked if they are sure that will fix the problem and I got the typical evasive answer. They gave me an estimate and the parts are less than $300, the rest is labour. They do repairs based on a fixed price, not hourly. I've had all sorts of weird repairs to do with this car: bearings at 50,000 mi (!!!!), broken suspension coil, now the speedometer. They told me this has never been reported in the Toyota repairs database.