Https://www.transmissionrepaircostguide.com/topic/no-reverse-2002-gmc-envoy-slt
http://www.fixya.com/cars/t13849301-03_gmc_envoy_will_not_go_in_reverse https://gmtnation.com/forums/threads/2003-trailblazer-ext-wont-move-when-engaged-in-drive-or-reverse.9590