Transmission will be in high gear starting out and will not down shift when I accelerate. The red light at the 2wd selection is red was green before.
Transmission in high gear from a stop, red light indicactor on 2WD is red on 2005 GMC Sierra 1500
scan trans codes and ck fluid level and condition
1 more answer
check tranny fluid levels and condition. review when last serviced. it may be due. bring to tranny shop for diagnostic run. tranny tech. will advise.