I have a 2006 Ford Expedition. I noticed a whine a couple months ago, thought it was power steering or something up front. After investigating, noticed it was come toward rear of engine. Was told it was probably a tranny issue. Tranny has been serviced, flush and fill and dropped the pan and replaced filter. Still makes noise. Shifts fine...very confusing. Hope someone can help with this.

 

As far reaching as it may sound, check the idler pulleys. I had a similar sound and it was the driver side smooth idler.
God Luck
rcode

 

Thanks for the reply, I will check it out. I did get under the car and while listening to the motor I had my wife get in and put it into gear (this takes a lot of trust, don't attempt this if your wife is mad at you) and that is when I noticed the sound came from the back of the motor, and the sound only happened when it was in gear...did your sound only come while in gear, or whenever the motor was running?

 

I have also experienced a partially clogged transmission filter cause the whining. Changing the fluid/filter would be a relatively inexpensive point to start. I'm assuming you've checked the level.
rcode

 

yes, I replaced the fluid an filter too, but couldn't get the torque converter, it didn't have a drain plug...looks like I'm probably spending some money, unfortunately.

 

Time for a stethoscope to pinpoint the sound. Best of luck, hope it's not too expensive.

 

Hello,
I have the same truck , an Eddie Bauer 2006. I noticed the whine few months ago.
I had already replacled my pulleys and tensioner.
I have also flushed my transmission and torque converter. all good.
My whine is also when the truck is on Drive.
I curious to know if you had yours fixed...
Also the whine is only when the engine transmission is hot....

 

At a pharmacy get yourself a Dr.'s stethoscope so you can listen to pin point sounds. Or a long screwdriver with a wood handle and put the tip on the noise and your ear on the handle.

A whine or any sound is vibration.
In hydraulics, vibration usually means 'air' [foam] and vibration is from air compressing.
Since liquids [ATF] will not compress but deliver force I'm thinking a pump problem, a low fluid level when hot problem, sucking air at a pick-up tube, a servo motor that could use a slight turn no the ban adjustment nut or something along those lines.

One could redo the fluid and filter replacement again. And since it is opened up you might want to take down the valve body, open it up and make sure it is absolutely pristine clean. Take you time, draw pictures, work on a clean bench with lots of room. And of course look~see at the bands on the servo motors.

If the fluid never became dirty and the fluid never became over heated hydraulics would never where out

skip.

 

Thanks for the advice, I will try that again. Never taken down the valve body before, so a little unsure of this step...I'll have to YouTube it and see what I can find.