i have a 99 blazer 4.3 4x4 the trany seems fine when i take off but it
won't shift up unless i let off the gas slightly then it wil shift and it does
the samething when i try to pass it will rev until i let off the gas slightly
i did change the fluid and filter cause the fluid didn't look the healthy.
thanks for any help you can give me enduro14

 

how many miles on the tranny? if alot, its time for a rebuild.