Q: Trouble code "transmission module unstable". on 1998 GMC Sonoma

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
code checker used shows a code "1870" trans module unstable, have cleared it several times, comes on after 40-75 miles. What are possible fixes? Where is transmission module?
(1) Answer
stop clearing the code and take it to a shop so they can see the freeze frame data to help them determine the problem. unless you have a scan too that can acess the info for the trans, throwing parts at it can be very expensive.