Transmission louder shifting

1997 Regal LS-floor column console

I notice when i shift into reverse it is more noticeable. Like more of a slight "clank". My Regal has 147.7km. Transmission filter and fluid was serviced at about 140km. However with synthetic and half regular ATF, as I bought too few synthetic (4L) at the time. But the Regal shifts good at cruising speeds. Only when in driveway now and then the shift is kinda fierce from park to reverse. Am I just worried for nothing??

feedback and comments appreciated

Thanks!

is the engine cold, and how fast is the idle? High idle will cause a harsh "P" to "R" engagement.

I'd do a pan drop and screen filter change. Get rid of any synthetic ATF and use dino Dextron-III only. The 4T65E may act weird with synthetic ATF. I don't think it is a good idea to mix the two.

Or you might need a fluid exchange service to get rid of all of it since a few quarts will still be left in the tranny such as the torque convertor.