Chevy Uplander transmission issue

2005 Chevrolet Uplander transmission issues

I have an Uplander that has not been driven much over the last year. I am getting ready to sell it and I noticed that the transmission was not going into reverse easily. It would eventually go into reverse. It also wouldn't go into drive readily. It also seemed to slam into gear when going forward. I changed the transmission fluid and things are better, but there still seems to be some reluctance when going into reverse. What could be causing the problem? Is there anything else I can check myself?

remove one quart fluid, put in one quart lucas tranny additive, drive100 miles, then sell the thing. One of the worse vans GM ever made, they don't make em anymore, and they had crap trannys

One of your customers has a 2008 Uplander with 50K miles on it and it's been falling apart since 40K. It's in your Chevy traction control video.