Harsh shift into reverse!

I have this '90 Lesabre and the transmission shifts smoothly and shifts into drive just fine. The problem is a very hard or "slamming" shift into reverse. Does this sound like a shift solonoid or something? Anybody have a similar problem on the same car? Also any particular area to check other than tearing down the transmission. Thanks

Check the modulator vacuum hose for a leak, or if it has any signs of transmission fluid on the inside of the hose.

There are quite a few TSB's regarding the issue. My wife's '89 LeSabre had the same issue. Before looking into the TSB's I did as suggested I replaced the vacuum modulator and mounts, no dice, the TSB outlines a internal problem.