I have the 4r70w in my 98 4.6L. If it sits outside for several hours when it's below 30 degrees, it will not shift into 3rd gear unless I am going 30 mph (not too many streets in my town are over 30). I let it warm up for 5-10 minutes each time I start it and after driving it for 5-10 minutes it sometimes still won't shift into 3rd. I haven't changed my tranny filter or fluid (I'm at 44825 miles). Should I and will that make a difference? I know the tranny fluid is like $5 a quart here. Any ideas?

Thanks,
Goat

 

I just recently had the accumulator piston replaced on the tranny. My over drive light was blinking. I got the code po728. I have the 4r70w also. It would do the same thing. Problem solved, I am very happy now. Total cost $180.00 with part included. My tranny looked real clean inside. I have 108,000 on it now.
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