99 Crown Vic Transmission Shudder Problem

Hi All: My brother has a 99 Crown Vic. I warned him that the trany fluid and filter needs to be changed at 30k miles to avoid the dreaded transmission shudder problem which is common on these cars. He claims he had it done, but the Bosos that did the work probalby ripped him off. They porbably said they did it, charged him but didn't do it.
Anyway, he now has a problem with transmission shudder.
The car has 38 K miles on it. He was going to look into warrantee coverage from Ford but I am not very hopeful. Does anyone know what it costs to repair the problem? I think it is related to the locking torque converter clutch. Any advice is greatly appreciated.

If the oil was changed, they probably didn't drain the converter. Dropping the pan drains about 1/3 of the total oil volume.
Draining the converter yields another TWO GALLONS of old oil. I'd bet that replacing the entire volume of oil will stop the shudder.

My fathers car had the exact same problem (98 crown vic with what we like to call a "push button overdrive". There is an additive, mabee the same mentioned in the above post from ford, that I put in it that halted the shudder immediatly, just dump it in