trans 4l60 issues

[Xxl2]

I have a 4l60 i lost all my forward gears wont even move forward. code is p 1870 Now my brake pedel is mush i feel like i lost my vacum where should i start Did i cook the trans? truck is 1997 c 1500 5.7

 

[1997]

google, 4L60E_80E_CODE_BOOK and 4L60E_UPDATE_HANDBOOK, should help you out.