I normally do not drive my wife's car and when I do its in 45 mph zones or less. Today I had to merge onto the expressway from the on ramp. I was doing about 50 mph and pressed the pedal to the floor the revs began building as it should and got all the way to 5000 rpm but the car remained at 45 mph....I quickly veered to the right on the grass right of way to avoid a collision..Upon continuing the car would accelerate all the way to 80 mph (did not attempt to go faster appeared it would). just by moderate pedal pressure. However upon stomping the pedal to the floor again the revs would climb to redline but the car would not go any faster. I have never since I got the car pressed the pedal to the floor and from talking to my wife neither has she. What could be the problem.

Thanks Rod

Follow Up: Spoke to a mechanic he asked if I had changed the tranny fluid. I advised no it was a sealed system but, was thinking of doing so now that the car has over 130000 miles. He advised it may be a sticking valve due to old fluid. By the way the transmission did not kick down when I stomped on it.

Its not a sealed for life tranny. Was, isn't any more and hasn't been for many, many years.

Current MB recommendations for the last 5 yrs or so is to change every 39K miles. Uses a syn fluid with a specific spec. Read up on it.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

Sounds like a transmission behavior to me. If you catch these transmissions wrongly, (when you trounce on the foot feed pedal) they will not shift or perform properly. Doesn't mean it will do it everytime though. Could have been a fluke. Mine's done it on occasion coming out of a toll road's toll plaza from a low-speed roll, when I've trounced on it. Nothing's wrong with my transmission. Trouncing on it may produce poor performance from low RPMs. Best go easy on the stabbing of the foot feed, so as not to endanger yourself by where the vehicle's surrounding traffic situation dictates.

Terry, will get the transmission oil changed asap...Joe it does it every time so I am wondering if its the oil or not. The tranny shifts smoothly and perfectly when accelerating slowly or moderately however NOT DURING HARD DRIVING.??????