Speedometer Cable Help

I have an 85 celica, ,manualMy speedometer doesnt work on it, and I was wodering if someone has a website that shows me how to install a new speed cable. Or if anyone has any experience on replacing a speed cable. Is it hard to reach the transaxle, do i need to do that if its just the inner cable? Which break is more typical, an inner or main speed cable? Thx in advance.