01 EX 7.3 (no performance mods) making an odd sound in lower gears when letting off throttle if held in a lower gear OR when trans shifts on its own under medium to hard accel. Best description of the sound: Say "CHEESE", but leave off the "SE". Just before it started doing this, I had the tranny flushed (by a transmission shop) and filled with Schaffer Full-Synth. Does not sound like transmission... but its hard to tell from where sound is coming.
No other issues... no loss of power, no slippage I can feel as different. Any ideas?
Any direction anyone could give would be greatly appreciated.

 

Does it sound like Darth Vaderr talking to you?

Look for an air leak somewhere before the mouth of the turbo. Could be the rubber ducting, could be the lid on your air box is loose, or????

The CHEE sound is distinctive, and sounds a little like a blower's blow-off valve .

Pop

 

Many thanks, Pop. It is definitely a "CHEE" only when going off throttle from medium to full throttle. I will carefully take a look at all you have suggested. Again, many thanks.

 

Come back and let us know what you find.

It will help the next guy by adding to this knowledge bank.

Pop