Ive encountered this several times. While driving both the "civilian" (FIA) vehicles, and driving NATO vehicles there will be moments where the vehicle will be "petal to the metal" so to speak and will hit the Rev limiter while not going top speed. However tapping the breaks and then gassing the vehicle (redneck shifting) will cause it to shift gears again and proceed as normal, ive seen this before 1.7 but appears to be more common by far now.

[this is only while using automatic shifting as far as I can tell.]