Hi there, my 2002 Sebring makes this clunk sound when I decelerate. Usually happens around 20m/hr or so. Only in "D" dosen't happen in third gear. It almost sounds like the car is downshifting. Any ideas?

 

How long has it been since you changed your transmission fluid?

 

Changed it recently, but that was first time since I bought it used 6 months ago.

 

Are you absolutely sure you put in the proper fluid? These transmissions are very sensitive to fluid characteristics. Check your owners manual (available at chrysler.com).
Check the fluid level. Engine running, level ground.
There is something you could try, but it will cost at least 50 bucks and may not work. Replace the solenoid pack. Shop on line for one, you can find them for about 50 bucks on eBay, and for about twice that elsewhere on the internet. They run about $200 -$250 at the dealership. It's not a difficult replacement, you remove the air cleaner, pull the cooler lines and the input speed sensor, remove three bolts and you pop it off.
There's no guarantee that it will cure the problem, but it may cure the leak you probably have. If it works, great. If not, at least you have fixed the leak.
Beyond that, you will probably need to have it pressure tested to see what is going on.
That's beyond the capability of most shade tree mechanics.
The transmission may also be throwing codes. They should be looked for with either a Chrysler DRB III scan tool or an OBD II scan tool.
Oh yeah, if you decide to replace the solenoid pack, it's a good idea to clean the area with de-greaser real well before you start.
Hope that helps.