abs light stays on and tranny wont shift out of first

[corova]

1994 full size blazer

the abs light has come on and the automatic transmission will not shift out of first gear. does this year have a speed sensor for the rear on the driverside of the tranny? how do i tell if the problem is the lft or the rt speed sensor on the front?
my first order of buisness will be to clean the sensors.
is there a way to disconect the abs and will this effect the tranny or will it just act like normal but with the ability to lock up the wheels.
i drive mostly in the sand on the beach. so the abs realy does not help me at all. thanks