96 blazer 4x4 shifting hard from D to R..

Im driving a 96 4dr 4x4 6cyl. and for awhile now i've noticed it shifts a little harder than usual from drive to reverse when parking. I almost never use 4wheel and my mechanic says the U joints are fine. Tranny fluid is good to. Also when leaving for work in the morning i notice that it sounds like its going faster than it is and taking a bit to shift into second until it warms up a bit. Just had a new computer and ignition switch put in last year. I have found lots of info here on the second problem but any input on the reverse thing would be helpful....thanx

My 94' has the same issue,
I hear a thump noise when I shift between D & R, nothing loud or really noticable,
But I hear it....

Just somthing you might want to check.... My 98 Blazer was running a little rough so I unplugged my MAF... When I did this I noticed shifting from D to R was hard and regular shifting was a little off... Plugged my MAF back in and it shifted fine....