You definitely have a problem with yours. Now my engines pretty worn out but a few years ago before it started falling apart I can remember being on an open stretch of highway w hardly any other people and it would sit at 105mph, that was about max w/out a downshift but it sat there for while no problem and felt solid.
Fastest ever was 116 coming down I90 on a long steep down hill coming down the mountain.

1989 Montero 4dr V6 3.0l