96 Blazer will barely reverse

Hello everyone..I have a 96 chevy blazer that's been a great car until now. I can barely get it to reverse. I have to let it warm up and then rev it up several times before it will slowly start to reverse. I've made sure it's full of tranny fluid..any ideas what this could be? Thanks

When my tranny started to go on my 99 Blazer 4x4 the first thing to go was the reverse gear and nearly immediately the lower (1st gear). It has something to do with the "sunshell". Do a search on yahoo or something for blazer transmission sunshell. You'll find a ton of hits. My tranny was a 4L60E with 158,000 miles.

Please dont keep driving this car until you change the filter and fluid .....remove both transmission lines from the radiator and blow through one to ensure the cooler is not clogged if it is you can install an aftermarket cooler pretty cheap ....I had the same problem years ago after adding an aftermarket cooler and a filter and fluid change it hasnt needed any attention for the last 8 years...it is getting about time for another filter and fluid change....