My toyota highlaner 2002 Limited with 70K has started giving this high engine noise around 60mph.
It sounds like the transmition is moving back into 3rd or 2nd causing he high engine noise.
This happens often when I stop or slow down to about 30 mmph and re-acelerate. Around 40 to 50 mph, the engine suddenly sounds like the transmition is stuck in 2nd and the engine noise becomes high, and as I continue to accelerate, the high noise will stop and everything will return to nomal.
All of this started about 3 months ago when the mileage was only 59K and I was driving 2 X 2 hours on the highway every week.
Could this be a transmitiion problem?