Hard to say. Don't want to say yes and it be a pos. Depending on the tranny, sounds like governor selenoid has gone out. Never done one on these but I know you got to dive into the tranny a little. Not a removal but take pan off and a few more steps. Or its a torque converter not going into lock up. $150 plus removal of tranny. And the Speedo not working is the the rear sensor in the tranny/transfer case(can't remember what its actual name is, output shaft speed sensor????????). Is easy fix, but I think it about $50 for the sensor.
But for $800 you have $400 more to play with to get it right. My 2 cents