4R100 upshifts very aggressive

[UAWBuilt]

My truck is a 1999 F-250 SuperDuty with a V-10 Gas Engine. At 135,000 miles it started upshifting very harsh (Last Monday). But only if taking off very slow. If I drive off like a teenager, it shifts and acts just fine. But driving like a grandpa, it upshifts very harsh. The Ford dealer has replaced the tranny filter, the solonoid pack and fluid in the torque converter and tranny. But I still have the same problem. I'm $500 into this and it seems like the mechanic is ready to build me a new house, but the back door is the only thing that needs fixed. The mechanic is going to make some phone calls, but I'm asking anyone here for some help to troubleshoot my problem. Update 9-13-2007 projectSHO89, thank you for your input. The Ford tech just wanted to keep guessing and changing various parts. I ended up taking my truck to a local Ma and Pa tranny shop. The problem was the torque converter. But not diagnosing it properly and the Ford Tech. taking it for multiple test drives caused the parts of the torque converter to flow into the tranny cooler and plugged it up and the small metal pieces went into the tranny. It is now a complete tranny rebuild, torque converter replacement and tranny cooler replacement. If the torque converter would have been replaced instead of the solonoid pack, the repair costs would have been much less. It pays to have a professional work on it. It's too bad the Ford tech was not an experienced tech.

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[projectSHO89]

Have him check for stored tranny codes, check tranny-related PIDs for the EPC circuit, and measure EPC and line pressures during self-test.

Steve

[UAWBuilt]

projectSHO89, thank you for your input. The Ford tech just wanted to keep guessing and changing various parts.
I ended up taking my truck to a local Ma and Pa tranny shop. The problem was the torque converter. But not diagnosing it properly and the Ford Tech. taking it for multiple test drives caused the parts of the torque converter to flow into the tranny cooler and plugged it up and the small metal pieces went into the tranny. It is now a complete tranny rebuild, torque converter replacement and tranny cooler replacement. If the torque converter would have been replaced instead of the solonoid pack, the repair costs would have been much less. It pays to have a professional work on it. It's too bad the Ford tech was not an experienced tech.