I have a 97 f350 crew cab 4x4 with E40D. I had the transmission serviced the other day and now I have a vibration that comes just before the truck shifts into overdrive then it goes away when it is in overdrive. Any ideas as to what happened and what I need to do to fix it.

 

does the Overdrive light flash at all? fluid still look nice a red? My guess would be that the torque converter is shuddering. I fix it by putting AFT+3 chysler tranny fluid in it if you decide thats what it is.

 

I talked to a Ford tech today and he said it that when the fluid was changed the mechanic must have put somthing besides mercron 5 in it. He said that would cause the torque converter to shudder. I'll be talking to the mechanic that serviced it tomorrow to see what he put in the transmission.