Tranny Differential Question

[scys]

I am in the middle of deciding if I should fix a 93 Corolla. The problem is that the differential is making a grinding noise, it drove home. It is a 3 speed auto and I am currious to know if I have to change the whole tranny or if the differential on the 3 speeds is a separtate unit that can just be changed? The deciding factor is going to be cost. Has been a great car with only 285 000km with hardly any rust.
Any advice or tips would be fantastic. This is my girlfriends car and she would rather drive it then my tercel.lol

Cy

[1steve]

Hello, the diff is a separate unit however depending whats wrong will determine if trans needs replaced. Visual inspection is in order to determine cause and cost of repair or replacement.

[scys]

Thanks,
It has been inspected by a guy we know (Mechanic) told us it was the differential and told us $800 to change the tranny. Seemed like an alright price however the car is not worth much, he suggested not fixing it which I agreed with, I told her it wasnt worth a new rad a month ago.lol.
Just thought it was a little odd that he called the other day to see if he could have the car to fix... to get it out of our way. I will look at it more closely and then fix or part it out.
I am sure the tranny is ok because it still moves but the diff make a horrible grinding sound.
Cy