I have a 2000 scab 5.4 liter automatic and whenever i slow down to a stop it seems that the trans stays in a high gear (3rd or overdrive) and gives me a snails pace acceleration out of stop signs and redlights. and the only time that it happens is when its really hot outside. california weather 104 degrees etc.
but the engine temp reads normal. A friend recomended a trans flush. Im thinking that the vescosity of the fluid has depleated from both the heat and the 57000 miles without a flush. help!

 

I'm having the exact same issue. It only seems to happen when the temperature gets around 93 degrees or higher. The acceleration is very slow and when the tranny shifts, it's almost a jerk. All guages are reading normal. My brother seems to think that the catylic converter is stopped up and is restricting flow which is causing the bad acceleration. Someone with any advice........please help.

 

does it take off anyfaster if you put the truck into manual low?

 

sounds to me like a slipping stator one way clutch in the torque convertor. the multiplication of torque only happens in the convertor if the clutch holds the stator stationary and redirects the vortex oil flow back to the turbine. if the clutch slips, it allows the oil to basically swirl back to the impeller and no multiplication happens.

after the truck gets up to about 70-80 kph ( or mph equiv) it drives normal ish? if it does then it will most likely need to have the convertor replaced. flushing out the oil may help, but once the clutch has slipped for a while it damages the stator shaft surface, and the sprags loose grip, and continue to slip until destruction.

good luck.

 

Saying that it "appears" to be in 3rd gear is the best way that I could describe the acceleration response. The engine itself doesn't get up to the normal RPM's when the accelerator is depressed.......again this only happens when the outside temp is above the 90's. I just had my engine replaced and experienced this with the old engine as well as the new one, so I've ruled the engine out as the culprit. One inclination is the tranny, but wouldn't the problem occur regardless of the temp?