Carl, thanks for the exploded view and I did what you suggested. I also added dental rubber bands to see if that helped and it did, However still a problem. Harmonyards, I looked for bent items but nothing is really obvious, although there is a bit of extra "droop in one of the coupler arms when the rubber bands are not on. The rubber bands snugged them both up to the coupling arm. I happen to have the same tank car in a Southern livery and the thumbtack on it is about 1/32 shorter than the PRR. apparently that is the difference- appears to be a manufacturing tolerance issue.
Have either of you taken this apart? I might price out some new trucks just for grins but I hate to destroy a tank car with disassembly. Seems the screw to hold the truck is on the inside or am I missing something on the exploded view?
Thanks for the help.