Toyota Repair: Speed Gear Replacement, vehicle speed sensor, wheel drive cars

Question
My wife said her 2002 Corolla, 4 cyl car had the engine light come on while driving and, at the same time, the speedomter and odometer stopped working. She also said the acceleration acted kind of inconsistant. My mechanic troubleshot and the trouble code was VSS (vehicle speed service inop). He checked the vehicle speed sensor and then found that the internal speed gear was spinning freely on the differntial hub connected to transmission. He said the only way to replace it , is to drop the transmission and would cost at least $1500 labor. The car has 105,000 miles on it so I really don't want to spend that kind of money. Is there any way it can be fixed without taking the transmission out ?  Also, it drives pretty well even with the existing problem and my Mass inspection sticker is not due until October. Am I doing any damage to transmission by driving it "as is" ?

Thanks- Dennis

Answer
Hi there,

You will not do any internal damage to the transmission driving it "as is". The problem with the under-drive (front wheel drive) cars like yours is that they're very compact. Therefore, most transmission repairs need to be done by removing the trans. Removing the trans from these cars is not en easy process. You have to remove the half shafts, move or disconnect the rack steering in some cases and cradle the engine. With a car that has that many miles on it, if it were my car, I would go ahead and install a new trans if I had the money and planned on keeping the car since the trans is being removed anyways.