At highway speeds around 50 to 70 mph my car has a surge almost like the transmission is slipping. it's hard to explain but it's like a redundent rrr rrrr rrr rrr rrr rrr and then it stops but it can do ti again at any time. You can actually feel the car slow down and then speed up again over and over. thanks Keith
slipping transmission on 2000 Pontiac Bonneville
by kparritt in Dowagiac, MI on January 16, 2010
ANSWER by patrick mannion , January 17, 2010
It does sound like a transmission or drivetrain problem which sounds like something that will soon fail. If it does turn out to be something simple at least it should be easy to diagnose as you can duplicate the problem for the mechanic consistently.