I just bought truck. Only has 63000 miles. After driving for a few days I started feeling a vibration. At first I thought I was running over rough spots in pavement like the warning marks on the shoulder. It starting doing it more frequent so I began taking notice of when it was doing it. Every time it does it it is changing into overdrive.It last about three seconds and it doesn't do it every time it goes into overdrive. There does not seem to be a pattern. No noise or vibration in other gears. Would appreciate any thoughts. Thanks.

 

It could be torque converter clutch shudder. A complete transmission fluid change often fixes this.

Here's how to do it yourself. Changing ATF Fluid in a E4OD and 4R100 transmission .: Articles

 

Tranny/torque conver going south or check your drive shaft and carrier bearing; U-joints. Hope that it is one of the latter, otherwise go to Sun Coast Diesel Transmissions - Home | Sun Coast Diesel Transmissions and look at a rebuild with a new TC.

Pap

 

I would start with a transmission flush. My wife's Taurus had these symptoms and a flush cured it for hers.

Good luck!

 

Thanks. I will give it a try. In the link about flushing it gives type of fluids based on the transmission I have. I dont have a book so how do I determine which one I have. Thanks.

 

A 2004 will have the 4R100

 

Thanks. I am getting supplys together to do a flush. I have read and heard a lot about friction modifer. Do I need to add this to the list of supplys. Thanks again for all the help.

 

Don't add friction modifier to the transmission!

 

How's the trans doing?

 

Changed ATF and filter. Have driven about 100 miles. So far no sign of problem. Still keeping fingers crossed. Thanks everyone for help.