95 Lumina trans slips on take off

I have 95 Lumina with a 3.1 engine and a 4T60-E transmission. This car has 172,00 miles. I have taken very good care of this car. It started this all at once as for as I can tell, I mean I had not noticed any thing out of the ordinary until last night I backed out of my drive and when I started to go forward I noticed that it slipped just a little before it went on. I drove it about 60 miles and each time I stopped it slipped a little more taking off. It does the same thing in reverse. It works fine after it takes off, no problem with passing gear or anything, just taking off it slipps. I changed the fluid and filter this morning, it did not help, I did not really think it would, because it had only been about 25,000 since I changed it. The fluid did not have a bad smell or color, nothing in pan. Any ideas would be greatly appreciated.
Thanks :banghead:

Hey guys
I did not get any responses, but I put a quart of a transmission helper called K&W in this morning and at the present my transmission is working great, I don't know how long it will last. I am hoping that I just had a valve sticking and this stuff has cleaned it up.!!! I have now driven this car 300 miles and it has not slipped once on take off.
:banghead:

Hey guys
I did not get any responses, but I put a quart of a transmission helper called K&W in this morning and at the present my transmission is working great, I don't know how long it will last. I am hoping that I just had a valve sticking and this stuff has cleaned it up.!!! I have now driven this car 300 miles and it has not slipped once on take off.
:banghead:

trans could just be getting old
my 91 was not engaging into gear on decell to accell
unless i stopped completely

and as misteriouly as it showed up
the problem went away