5R55E - becoming a problem

[Domen]

1500 miles ago I changed tranny oil. Ford diler recommended Castrol ATF Dextron III. After 1000 miles I noticed changes in shifting from 2nd to 3nd and reverse became slow. After searching the forum I realized that they gave me wrong oil. Went to a Ford dealer and proof them wrong. Gave me original Ford oil instead.

Now I changed the oil and immediately noticed a strange sound coming from tranny. I think it is tranny because it is hard too diagnose. I'm sure it is coming from the front of the truck. It sounds like high pitch whistle (like metal to metal friction). It becomes louder if I accelerate. It is also hard to notice. At least for now.

The intensity is also changing when driving on the highway at 60 miles. When the car is swinging up and down because the highway is not 100% flat the sound changes from high intensity to low.

My mechanic thinks it is all in my head but I know the truck did not have that sound before changing to mercon v oil.

After changing oil tranny started to work great. And it still does! Except the metal sound that worries me more and more.

Please help and sorry for poor english.

 

[ARTURPOLAND]

Hi

Did they also change the oil filter ?? maybe it is the problem

 

[Domen]

Filter was not changed because it is almost new. It was changed on first change oil (for dextron III). Strange sound becomes noticable only when running over 30 miles. In full stop and in drive there is no sound. I also tried running highway at 60 miles and turning engine off and tranny in neutral. The calttering sound stays .

 

[Domen]

Please HELP!