Transaxle speed sensor?

Is there a transaxle speed sensor? We had the vss replaced and the speedometer is still dropping out on our 98 Windstar. Someone at the dealership (which replaced the vss) said that it could be the transaxle speed sensor. If so, does anyone know where it is at? and would this correct our problem?

Also another subject, we replaced the the front brakes a month ago. Since then, the ABS light comes on when we reach approx. 70 mph. Does anyone know why?

In addition, we keep losing power steering fluid. Any ideas? I am so sick of this van. Any help would be greatly appreciated.

Thank you and Have a great day!

Hi
My manual shows a turbine shaft speed sensor, but indicates that it is used for internal transmission control of torque converter etc. Don't know that it would affect the speedo.