Make sure your fluid isnt low for starters

Trans problems are hard to diagnose spot on, but I would recommend a trans oil change, and add something like trans X to it.
It might not be called trans x...... I think the last time I had a trans issue I used a product by the seafoam makers for transmissions. LUCAS might also make something as well.
YOu might be able to just dump a can in on top of what is in there now....... but I would still recommend changing it myself.

When you change the fluid, you drop that pan, and 5 quarts or so will come out. Then replace the filter and the gasket and use a gasket sealer as well. clean everything really well, including the magnet in that pan. I use cheap brake cleaner and let it air dry really well. The transmission is hydraulic so it is best when clean.
When adding the trans fluid, read what the LUCAS or seafoam says, sometimes they replace a quart of fluid, sometimes you just dump in on top of whats in there.

The seafoam or LUCAS will cause seals to swell some and renew clutch faces, etc. It is what I do before the worst case scenario of having it rebuilt or buying a rebuilt and putting it in.

Some people say not to change the fluid in the trans, they think that is where more problems happen, but I dont think that is a issue, so this is just my opinion based on what I have done in the past on vehicles I have owned and working with friends.
If you do change it, I would think about adding a drill in plug (installed while the pan is off the trans) and that helps facilitate a trans oil change later, I put one on mine, and now I can ghange without changing the filter, and do it once a year. When that fluid change is done you dont change all the fluid, only 2/3rds of the total fluid comes out. that is why I change mine yearly, a little bad mixed with the good.

PM me if you need anymore details.
Good luck