Some references in this thread are referring to Jasper trans as being different from Ford trans. Jasper rebuilds OEM units and does not produce anything themselves. They were once thought of as junk, but they have stepped up their game in the last 10 years or so. They also offer a HD version of the 4R100 like Ford does. In both cases the HD versions are about $1000 more. Both have 3yr/100,000 mile warranties.
The issue she is having makes me want to look at electronics more than mechanics. Broken parts don't heal themselves temporarily so that test drives can't duplicate problems. Does sun or rain have any affect? Towing or not? The Super Duty body of those years had a rust issue in the upper left corner of the w/shield causing water to get into the PCM mounted below that area. Is it getting worse with time?
The noise baffles me. The sound described would be from a thin piece of something flexing like a fuel tank shield or a exhaust shield. Has anybody checked the engine and trans mounts or body mounts? I don't think the noise is related to the trans issues.
