If it's a manual, it's the clutch slipping.

If it's an ATX, the tranny or the torque converter is slipping.

This observation is due to your report that the engine speed continued to increase with no change in wheel speed.

Steve

98 Contour SE Sport 2.5 Duratec ATX The wifey's car 89 Taurus SHO - 246K miles 94 SHO ATX - 190K 1997 F-150 5.4L ATX - The Workhorse 150K. ANY THREAD WITH "OMG" or "WTF" ETC IN THE TITLE WILL BE IGNORED!