ok well i think i got it narrowed down a bit.

bushings, u-joints, drive line, everything seems ok and good to go. got it lubed up today and took it for a drive where i know it was doing it.

guess what, still doing it. so i went back and did the same drive over again with the overdrive off. it didn't do it this time. ok so maybe fluke maybe not, but it seems to be almost like it shifts into overdrive at 40 mph but cruising at 38-42 it's like it wants to shift out. i'm thinking it has something to do with the over drive shift points. driving faster (in overdrive) or slower in 4th gear it doesn't do it. so who knows what is going on.

other than that "it's the road"

thanks for all your help guys.

 

Not to rain on your parade, but the first time my trans went, it was different isuues but the torque converter was fried and the fragments got all through the trans. Mine had a slight shudder at 45-50 and on the highway instead of kicking down the trans. when picking up speed, the RPMs would just rise about 500. The warranty covered it and you know they wouldn't change the whole thing if they didn't have to. Hopefully if it is the converter, you can switch it out before it adds to the trans.