"Klunk" when shifting into 2nd gear

[Steve Bakken]

I need to pick some brains here. My folks are looking at buying an all original '87 Supreme that was recently traded into the local dealership by the original owner. Looks very clean according to the pics on the website. I can't get there to look at it myself. They test drove it and said it ran great but there's a "klunk" when it shifts into 2nd. It's a 307 car so I'm assuming a 200R4 in it. Both my cars have the th350 so I'm not super familiar with the quirks of this trans. I'm guessing just a sticky valve and in need of a flush and filter but I don't want to steer them wrong either.

 

[MontesbyE]

Its probably in need of a filter change and new fluid. The TV cable could be out of adjustment as well. The 2004r is known for having a snappy 1st-2nd shift. Transmission mount is probably disintegrated. that would cause a clunk I'm sure.
If the car is clean as you think, pull the trigger and deal with the issues. My opinion...