Slight thump with going into and sometime out of overdrive, Transmission/Torque Converter/Overdrive?

JCONAWAY

MEMBER
2003 FORD EXPEDITION
5.4L
V8
2WD
AUTOMATIC
315,000 MILES

Slight thump with going into and sometime out of overdrive. Some slippages when driving at about 60 MPH and accelerating. If it shifts out of overdrive the slippage goes away. I have been to three garages to have the transmission serviced and told three times they would not do the service on a transmission with that many miles. I had it serviced about 100k ago but not since. Thoughts on should I continue to look for a place to change the fluids? Should I just change the fluid by removing and replacing from the fill tube? Should I leave it alone and replace later? It is the torque converter that needs replacing?

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,700 POSTS

Hi,

Is the fluid full and clean? Does it have a burnt smell or very dirty?

The concern the shops have is that they could make it worse if they service it at this point. If the fluid is extremely dirty and new fluid is installed, it can cause a slip. Basically, the new fluid has a detergent in it. With this many miles, the dirt in the transmission may actually be helping the clutches not to slip. If new fluid cleans the dirt out, it could begin to slip.

Next, if you turn the OD off, do you have any slippage? If not, it could be a pressure-related issue. Does the check engine light stay on when the engine is running, or have you had the computer scanned for diagnostic trouble codes that could be related to the transmission?

Let me know.

Joe