'08 Expedition 6R75 noise heard under load

mchan68 · August 12, 2009

Good evening gents. I have one here, that I've been asked to drive home for the evening. Vehicle description is in the thread title. The complaint is a one time unwarranted traction control event, as I understood it during acceleration.

The second complaint (the one that can be duplicated), is a "grunt", "buzz" or "squeak" noise heard during moderate to heavy acceleration. Apparently, the duration of the noise is greater at highway speeds, hence the request for me to drive the vehicle home. Apparently, our shop foreskin thought it to be a "heat shield buzz" when he heard the noise. Vehicle was already placed on a lift to check for loose heat shields.

Customer already took me for a brief road test in the city streets to indicate the noise. To me, it sounds more like a "ratcheting" type noise, like a driveline component slipping. Checked OASIS. Found TSB article 09-6-1. Funny enough, during the drive home I can almost duplicate the sound when accelerating in a manner where a downshift to 3rd is warranted. I'm not a tranny guy, so I was just wondering if any of you have come across this particular issue before? Has anyone actually had a 6R75 apart for this TSB yet?

Brad Clayton · August 12, 2009

You sure you don't have and IWE trying to engage. Seen alot of them on these go out and cause the noise you are desribing.

mchan68 · August 12, 2009

You sure you don't have and IWE trying to engage. Seen alot of them on these go out and cause the noise you are desribing.

Funny you should ask that. I tried playing around with the 4WD selector switch as the customer was driving, and there was no change in the noise. Noise is heard while in 2WD or 4WD.